Basal Plane Research Articles

A two-step modeling method for constructing 3D negative Poisson’s ratio materials with high specific strength based on common lattice structures

The traditional negative Poisson’s ratio (NPR) structure was basically designed based on concave or rotational mechanisms, resulting in relatively low specific strength and limiting its application. This paper proposed a two-step modeling method to establish a connection between the common lattice structures and NPR structures, which can obtain NPR structures with high specific strength. The models with different triaxial compression ratios were obtained through triaxial compression FE simulation to the selected initial configuration. Then, the mechanical properties of these models were studied through uniaxial compression FE simulation and experiments. In the research scope of this paper, the results demonstrate that the lattice structure can get NPR through the two-step modeling method when the Maxwell’s number is less than or equal to zero. The specific strength of the NPR structure obtained through the two-step modeling method was at most 1.5 times higher than that of the traditional 3D star-shaped NPR structure. Due to the high designability and excellent mechanical properties of lattice structures, this work provides a novel method for the manufacture of NPR structures with high specific strength.

Evaluating load-bearing and hypervelocity impact shielding capabilities of face-centered cubic lattice core sandwich panels

In the present paper, a comparative study on load-bearing as well as hypervelocity impact shielding performance of sandwich panels with face-centered cubic (FCC) lattice core is numerically performed in order to evaluate their competency in satellite structure applications. To this end, 5A06 aluminum alloy FCC and FCCz beside cube and octahedron lattice structures with similar areal densities were investigated. Whipple shield structure of same material and areal density was also studied in order to be compared to lattice structure in protection field. The present study simulates hypervelocity impact of a spherical projectile with 2 mm diameter, represents the space debris, collides with the structures at the velocity range of 2–6 km/s. Numerical simulation model was validated by performed experimental study. Authors were inspired by cube and FCCz topologies to propose a novel lattice structure could provide outstanding shielding and load-bearing capabilities in comparison to the other structures studied in this research. Furthermore, the detailed effects of projectile impact location on the protection performance were investigated and the mentioned item was found to have considerable influence on the structure shielding performance.

Temporal Evolution of Defects and Related Electric Properties in He-Irradiated YBa2Cu3O7-δ Thin Films.

Thin films of the superconductor YBa2Cu3O7-δ (YBCO) were modified by low-energy light-ion irradiation employing collimated or focused He+ beams, and the long-term stability of irradiation-induced defects was investigated. For films irradiated with collimated beams, the resistance was measured in situ during and after irradiation and analyzed using a phenomenological model. The formation and stability of irradiation-induced defects are highly influenced by temperature. Thermal annealing experiments conducted in an Ar atmosphere at various temperatures demonstrated a decrease in resistivity and allowed us to determine diffusion coefficients and the activation energy ΔE=(0.31±0.03) eV for diffusive oxygen rearrangement within the YBCO unit cell basal plane. Additionally, thin YBCO films, nanostructured by focused He+-beam irradiation into vortex pinning arrays, displayed significant commensurability effects in magnetic fields. Despite the strong modulation of defect densities in these pinning arrays, oxygen diffusion during room-temperature annealing over almost six years did not compromise the signatures of vortex matching, which remained precisely at their magnetic fields predicted by the pattern geometry. Moreover, the critical current increased substantially within the entire magnetic field range after long-term storage in dry air. These findings underscore the potential of ion irradiation in tailoring the superconducting properties of thin YBCO films.

Ultrafast Laser Manipulation of In-Lattice Plasmonic Nanoparticles.

Plasmonic nanoparticles enable manipulation and enhancement of light fields at deep subwavelength scales, leading to structures and devices for diverse applications in optics. Despite hybrid plasmonic materials display remarkable optical properties due to interactions between components in nanoproximity, scalable production of plasmonic nanostructures within a single-crystalline matrix to achieve an ideal plasmon-crystal interface remains challenging. Here, a novel approach is presented to realize efficient manipulation of in-lattice plasmonic nanoparticles. Employing ultrafast-laser-driven plasmonic nanolithography, metallic nanoparticles with controllable morphology are precisely defined in the crystalline lattice of yttrium aluminum garnet (YAG) crystal. Through direct ion implantation, hybrid plasmonic material composed of nanoparticles embedded in a sub-surface amorphous YAG layer is created. Subsequently, femtosecond laser pulses guide formation and reshaping of plasmonic nanoparticles from the amorphous layer into the single-crystalline matrix along direction of light propagation, facilitated by a plasmon-mediated evolution of laser energy deposition. By tailoring resonance modes and optimizing the coupling between structured particle assemblies, a range of applications including polarization-dependent absorption and nonlinearity, controllable photoluminescence, and structural color generation is demonstrated. This research introduces a new approach for fabricating advanced optical materials featuring in-lattice plasmonic nanostructures, paving the way for the development of diverse functional photonic devices.

Controllable Growth of Crystal Facets Enables Superb Cycling Stability of Anode Material for Potassium Ion Batteries

AbstractTo enrich the crystal growth strategies for the booming applications concerning lattice structure, a preferred facet‐growth method is proposed for solvothermal synthesis of target (BiO)2CO3 in the two‐phase system. The dominant crystal phase can be regulated from α‐Fe2O3 to (BiO)2CO3 by properly increasing dosage of Bi feedstock, and the optimized composite is composed of (BiO)2CO3 nanocrystal (≈10 nm) and amorphous iron oxide (defined as “FOB‐50”). Based on experimental characterizations and theoretical calculations, the highly matched lattice between (006)/(0012) facets of α‐Fe2O3 and {010} facet group of (BiO)2CO3 involving orientation of Fe─O─Fe bond and Bi─O─Bi bond is verified to facilitate the interaction between the above facets, resulting in preferred growth of {010} dominated by (040) facet in (BiO)2CO3 and its composites. The structural merits can not only enable the FOB‐50‐based electrodes to achieve a high capacity and unprecedentedly stable cyclic performances for 1500 cycles/a long time‐span of 32 months as anode materials, but also ensure the full‐cell to well inherit the electrochemical features of the cathode in potassium ion batteries (PIBs). This work can provide new insight into lattice regulation for bismuth‐based materials and expand their application as electrodes for high performance PIBs and lithium ion batteries.

Analytical and numerical modeling on strengths of aluminum and magnesium micro-lattice structures fabricated via additive manufacturing

AbstractBioinspired lattice structures have a wide range of applications in aerospace, automotive, energy, and medical device industries due to their high strength-to-weight ratio. Although experimental and numerical modeling methods have been extensively used to characterize the compressive behavior of lattice structures, an accurate analytical model has great values in material/structure designs and applications. In this study, a new analytical model is developed for two configurations based on limit analysis in the plasticity theory to predict the compressive strengths of micro-lattice structures (MLS). The model is also discussed for determining the amounts of stretching-dominated deformation and bending-dominated deformation. A comparative study is performed between analytical solutions and experimental results of AlSi10Mg (aluminum alloy) and WE43 (magnesium alloy) MLS additively manufactured via selective laser melting (SLM). Finite element simulations using beam elements are conducted to evaluate the accuracy of the analytical solution. Analytical results, finite element simulation results, and the experimental results are in a good agreement with both AlSi10Mg and WE43 MLS. The shear band formation, as a main failure mode of MLS, is also studied and evaluated using the classical Rudnicki–Rice’s criterion, for which a reasonably good accuracy is demonstrated.

Enhanced mechanical and thermophysical properties of Mg2Ca, Al2Ca, and Al4Ca bulk metallic glasses in comparison to crystalline alloys for bone grafting applications: A molecular dynamics investigation

We investigate the glassy-state properties of Mg2Ca, Al2Ca, and Al4Ca from the grafting application viewpoint. We employed classical molecular dynamics to examine the phase transition, structural, thermodynamic, transport, and mechanical properties in the amorphous state. All properties suggest successful simulations of the glass phase at and below the glass transition temperature, ranging between 550 and 689 K for Mg2Ca, Al2Ca, and Al4Ca. Computed results are compared and discussed with the reported findings and known mechanical and thermal properties of the various parts of the human bones and biocomposites. The comparison establishes that the mechanical, thermal, and transport properties significantly improve in the glass phase compared to its crystalline alloy form. At 300 K, studied glasses have densities in close agreement with human bone density. Structural analysis and heat capacity show the second-order phase transition, verifying the formation of the glass structure. The targeted glasses exhibit excellent thermal conductivity and thermal diffusivity compared to other commonly used biocomposites for bone grafting. Furthermore, the simulated elastic properties, viz., the Poisson ratio, G/B ratio, Cauchy's pressure, and yield strength, are in close agreement with the mechanical properties of various parts of human bone. The predicted ductility nature, contrary to the brittle character of Mg2Ca, Al2Ca, and Al4Ca crystalline alloys, proves the superiority of the glassy form for the implant's functioning. The minimum enthalpy of formation and thermodynamic stability of studied compounds benefit the synthesis process; hence, we propose that the studied glasses are persuasive materials for experimental synthesis aimed at bone grating applications.

Two-dimensional platinum borides: A Dirac nodal line quantum electrocatalyst for efficient hydrogen evolution reaction

Two-dimensional (2D) catalysts exhibiting high carrier mobility, near-zero Gibbs free energy (ΔGH*), and an active basal plane are highly desirable for optimizing the hydrogen evolution reaction (HER). However, fusing these attributes within a solitary material encounters profound difficulties. Utilizing density functional theory (DFT) calculations, we have identified the PtB2 monolayer is such a candidate, demonstrating exceptional dynamical, thermal, and mechanical stability. The band structure analysis reveals that the PtB2 monolayer features double Dirac points along its high-symmetry lines. The estimated Fermi velocity of the PtB2 monolayer is as high as 7.8×105m/s, close to that of graphene. By scanning the Dirac points in the first Brillouin Zone, the Dirac points constitute a nodal-line semimetal with a loop centered at the Γ point. This nodal line is anticipated to facilitate charge transfer between the catalyst surfaces and reaction intermediates, potentially enhancing catalytic efficiency. Importantly, PtB2 monolayer boasts superior HER performance, with a nearly zero ΔGH* of 0.057 eV at its boron-dominant sites. The application of a subtle 1% strain serves to reduce its ΔGH* to an even more favorable −0.003 eV, suggesting significantly improved HER capabilities. When layered in a bilayer form, the PtB2 exhibits van der Waals (vdW) type interlayer interactions. Remarkably, we found that varying the stacking order can effectively alter the nodal line's shape and, accordingly, the PtB2 layer's catalytic properties. The distinctive combination of a Dirac nodal line, ideal Gibbs free energy, and expansive active sites positions the PtB2 monolayer as a competitive 2D quantum catalyst for hydrogen production.

Preparation and Evaluation of Clarithromycin Taste-Masking Dry Suspension Using Hot Melt Extrusion Based on Solid Dispersion Technology.

Clarithromycin (CLA) is the preferred drug for treating respiratory infections in pediatric patients, but it has the drawbacks of extreme bitterness and poor water solubility. The purpose of this study was to improve solubility and mask the extreme bitterness of CLA. We use Hot Melt Extrusion (HME) to convert CLA and Eudragit® E100 into Solid Dispersion (SD). Differential scanning calorimetry (DSC) and Powder X-ray diffraction (PXRD) were used to identify the crystalline form of the prepared SDs, which showed that the crystalline CLA was converted to an amorphous form. At the same time, an increase in dissolution rate was observed, which is one of the properties of SD. The results showed that the prepared SD significantly increased the dissolution rate of crystalline CLA. Subsequently, the SD of CLA was prepared into a dry suspension with excellent suspending properties and a taste-masking effect. The bitterness bubble chart and taste radar chart showed that the SD achieved the bitter taste masking of CLA. Principal components analysis (PCA) of the data generated by the electronic tongue showed that the bitter taste of CLA was significantly suppressed using the polymer Eudragit® E100. Subsequently, a dry suspension was prepared from the SD of CLA. In conclusion, this work illustrated the importance of HME for preparing amorphous SD of CLA, which can solve the problems of bitterness-masking and poor solubility. It is also significant for the development of compliant pediatric formulations.

Neural networks for emergent behavior in biological microstructures

PurposeThis paper develops a neural network surrogate model based on a discrete lattice approach to investigate the influence of complex microstructures on the emergent behavior of biological networks.Design/methodology/approachThe adaptability of network-forming organisms, such as, slime molds, relies on fluid-to-solid state transitions and dynamic behaviors at the level of the discrete microstructure, which continuum modeling methods struggle to capture effectively. To address this challenge, we present an optimized approach that combines lattice spring modeling with machine learning to capture dynamic behavior and develop nonlinear constitutive relationships.FindingsThis integrated approach allows us to predict the dynamic response of biological materials with heterogeneous microstructures, overcoming the limitations of conventional trial-and-error lattice design. The study investigates the microstructural behavior of biological materials using a neural network-based surrogate model. The results indicate that our surrogate model is effective in capturing the behavior of discrete lattice microstructures in biological materials.Research limitations/implicationsThe combination of numerical simulations and machine learning endows simulations of the slime mold Physarum polycephalum with a more accurate description of its emergent behavior and offers a pathway for the development of more effective lattice structures across a wide range of applications.Originality/valueThe novelty of this research lies in integrating lattice spring modeling and machine learning to explore the dynamic behavior of biological materials. This combined approach surpasses conventional methods, providing a more holistic and accurate representation of emergent behaviors in organisms.

Structural Complexities in Sodium Ion Conductive Antiperovskite Revealed by Cryogenic Transmission Electron Microscopy.

We use low-dose cryogenic transmission electron microscopy (cryo-TEM) to investigate the atomic-scale structure of antiperovskite Na2NH2BH4 crystals by preserving the room-temperature cubic phase and carefully monitoring the electron dose. Via quantitative analysis of electron beam damage using selected area electron diffraction, we find cryogenic imaging provides 6-fold improvement in beam stability for this solid electrolyte. Cryo-TEM images obtained from flat crystals revealed the presence of a new, long-range-ordered supercell with a cubic phase. The supercell exhibits doubled unit cell dimensions of 9.4 Å × 9.4 Å as compared to the cubic lattice structure revealed by X-ray crystallography of 4.7 Å × 4.7 Å. The comparison between the experimental image and simulated potential map indicates the origin of the supercell is a vacancy ordering of sodium atoms. This work demonstrates the potential of using cryo-TEM imaging to study the atomic-scale structure of air- and electron-beam-sensitive antiperovskite-type solid electrolytes.

Effect of Pore Architecture of 3D Printed Open Porosity Cellular Structures on Their Resistance to Mechanical Loading: Part I – Experimental Studies

Abstract The development of additive manufacturing (AM) techniques has sparked interest in porous structures that can be customized in terms of size, shape, and arrangement of pores. Porous lattice structure (LS, called also lattice struct) offer superior specific stiffness and strength, making them ideal components for lightweight products with energy absorption and heat transfer capabilities. They find applications in industries such as aerospace, aeronautics, automotive, and bone ingrowth applications. One of the main advantages of additive manufacturing is the freedom of design, control over geometry and architecture, cost and time savings, waste reduction, and product customization. However, the designation of appropriate struct/pore geometry to achieve the desired properties and structure remains a challenge. In this part of the study, five lattice structs with various pore sizes, with two volume fractions for each, and shapes (ellipsoidal, helical, X-shape, trapezoidal, and triangular) were designed and manufactured using selective laser sintering (SLS) additive manufacturing technology. Mechanical properties were tested through uniaxial compression, and the apparent stress-strain curves were analyzed. The results showed that the compression tests revealed both monotonic and non-monotonic stress-strain curves, indicating different compression behaviors among the structures. The helical structure exhibited the highest resistance to compression, while other structures showed similarities in their mechanical properties. In Part II of this study provides a comprehensive analysis of these findings, emphasizing the potential of purpose-designed porous structures for various engineering applications.

Chiral dynamics in soft triaxial nuclei

The chirality in soft triaxial nuclei is investigated for the first time with the time-dependent and tilted axis cranking covariant density functional theories on a three-dimensional space lattice in a microscopic and self-consistent way. Taking the puzzling chiral nucleus 106Ag as an example, the experimental energies of the observed nearly degenerate bands are well reproduced without any free parameters beyond the well-defined density functional. A novel chiral mode in soft triaxial nuclei is newly revealed from the microscopic dynamics of the total angular momentum. This opens a new research area for the study of chirality, particularly in relation to soft nuclear shapes.

Matching in Networks: Structure of the Set of Stable Allocations

Matching models with contracts have been extensively studied in the last years as a generalization of the classical matching theory. Matching in networks is an even more general model in which firms trade goods via bilateral contracts constituting a supply chain. Hatfield and Kominers ([2012] Matching in networks with bilateral contracts, Am. Econ. J., Microecon. 4(1), 176–208, doi:10.1257/mic.4.1.176) showed that a natural substitutability condition characterizes the maximal domain of firm preferences for which the existence of stable allocations is guaranteed in such a model, if the set of all existent contracts is acyclic. Moreover, they asserted that these conditions are sufficient to obtain a suitable lattice structure for the set of all stable allocations. In this paper, we exhibit an inconsistency in the last point through an example, and introduce an additional condition over firm preferences that allows to recover an appropriate lattice structure.

Ag-Coated Super Duplex Stainless Steel AISI2507 with or without Crystallization of Secondary Phase as Advanced Li-Ion Battery Case Material

Li-ion batteries used in portable electronic devices and electric vehicles require high safety standards, necessitating the use of high-performance structural materials for battery casings. Super duplex stainless steel (SDSS) is a structural material suitable for portable electronic products owing to its excellent strength and corrosion resistance. SDSS AISI2507 was used to construct a Li-ion battery casing, a Ag coating was applied via physical vapor deposition (PVD) after the heat treatment of AISI2507 with or without a secondary phase, and the coating thickness was controlled by varying the PVD time. The thickness of the Ag coating layer increased proportionally with time, thereby enhancing the electrical conductivity. The structure and coating behavior were confirmed using FE-SEM, XRD, and GDS. The secondary phase was crystallized by the segregation of the alloy and formed a BCC structure. The FCC lattice structure exhibited excellent coating behavior on the austenite (FCC structure) of AISI2507. Conversely, the secondary phase exhibited low adhesion owing to differences in composition and crystal structure. However, the Ag coating layer on AISI2507 exhibited excellent electrical conductivity, outperforming conventional Ni-plated Li-ion battery casings comprising AISI304. However, the precipitation of the secondary phase must be controlled, as the formation of the secondary phase acts as a factor that decreases electrical conductivity from 58.8 to 53.6 (ICAS) %. The excellent performance of Ag-coated AISI2507 makes it suitable for the fabrication of enhanced Li-ion battery casings.

Assessing Hydrogen Embrittlement in Pipeline Steels for Natural Gas-Hydrogen Blends: Implications for Existing Infrastructure

Governments worldwide are actively committed to achieving their carbon emission reduction targets, and one avenue under exploration is harnessing the potential of hydrogen. Blending hydrogen with natural gas is emerging as a promising strategy to reduce carbon emissions, as it burns cleanly without emitting carbon dioxide. This blending could significantly contribute to emissions reduction in both residential and commercial settings. However, a critical challenge associated with this approach is the potential for Hydrogen Embrittlement (HE), a phenomenon wherein the mechanical properties of pipe steels degrade due to the infiltration of hydrogen atoms into the metal lattice structure. This can result in sudden and sever failures when the steel is subjected to mechanical stress. To effectively implement hydrogen-natural gas blending, it is imperative to gain a comprehensive understanding of how hydrogen affects the integrity of pipe steel. This necessitates the development of robust experimental methodologies capable of monitoring the presence and impact of hydrogen within the microstructures of steel. Key techniques employed for this assessment include microscopic observation, hydrogen permeation tests, and tensile and fatigue testing. In this study, samples from two distinct types of pipeline steels used in the natural gas distribution network underwent rigorous examination. The findings from this research indicate that charged samples exhibit a discernible decline in fatigue and tensile properties. This deterioration is attributed to embrittlement and reduced ductility stemming from the infiltration of hydrogen into the steel matrix. The extent of degradation in fatigue properties is correlated not only to the hydrogen content but also to the hydrogen permeability and diffusion rate influenced by steel’s microstructural features, with higher charging current densities indicating a more significant presence of hydrogen in the natural gas pipeline blend.

Effect of substituted cobalt–chromium–iron oxides’ dissolution kinetics in oxidizing formulation on decontamination process

AbstractRemoving radioactive corrosion products from Cr-containing iron oxides require a multi-step and multi-cycle decontamination process. The present article brings out the effect of divalent metal ion substitution on the release rate of chromium in the oxidative pre-treatment step. The non-stoichiometric cobalt chromium ferrites were synthesized, characterized and effect of Zn2+/Ni2+ substitution on the dissolution behavior was probed. The dissolution rates decreased with increasing the degree of inclusion and showed minima at ~ 0.4–0.6 atom% which is explained on the basis of lattice structure. It is concluded that the dissolution kinetics of native nickel–chromium ferrites in reactors increases with metal ion inclusion.

Vortex lattice state transitions in water surface waves

Surface waves can generate an ordered vortex lattice of fluid particles on the air-water interface. Here, the transitions of the lattice structure are observed through experiments and modelled analytically. A fully-immersed square waveguide system is positioned at the center of a larger bath which directs particles into counter-rotating vortices. Flow interactions with the bath free-surface alter the ordered structure, and a state transition is initiated by the increase of the waveguide immersion depth. It manifests as a change in the orbital momentum and spin properties of the vortices, and develops through the combination of reflected-wave attenuation and mean flow effects from the classical Stokes drift and Eulerian currents. Transitions from a perfect antiferromagnetic state to weakly-ordered ones are achieved, including a monopole vortex reminiscent of spectral condensates in thin fluid layers. Order in the disordered flow is uncovered through velocity field corrections after invoking time-scale separation. The lattice structures are modelled analytically through a superposition of mean flow contributions from the waveguide and bath modes. The results open a new platform for investigating the dynamics of wave and vortex lattice interactions, and devising new techniques to characterize complex flow phenomena on the air-water interface.

Tuning Stark effect by defect engineering on black titanium dioxide mesoporous spheres for enhanced hydrogen evolution

Defects can strongly affect the lattice, strain, and electronic structures of nanomaterials photocatalysts, like a double-edged sword of both positive significance and negative influence on photocatalytic performances. To date, most studies into defects only partially elucidated their beneficial or detrimental roles in photocatalysis. However, a quantitative understanding of the photocatalytic performances modulated by defect concentration still needs to be discovered. Here, a series of TiO2−X mesoporous spheres (MS) with different oxygen vacancy concentrations for photocatalytic applications were prepared by high-temperature chemical reduction. The link between oxygen vacancy concentration and photocatalytic performance was successfully established. The localization of carriers dominated by the Stark effect is first enhanced and then weakened with increasing oxygen vacancy concentration, which is a crucial factor in explaining the double-edged sword role of defect concentration in photocatalysis. As the reduction temperature rises to 300 °C, carrier localization dominated by the quantum-confined Stark effect maximizes the separation ability of photo generated electron hole pairs, thus exhibiting the best catalytic performance for photocatalytic hydrogen production and the degradation of organic pollutants, as demonstrated by a hydrogen evolution rate of 523.7 µmol g-1 h-1 and a ninefold higher RhB photodegradation rate compared to TiO2 MS. The work offers excellent flexibility for precisely constructing high-performance photocatalysts by understanding vacancy engineering.

Fuzzy object-induced network three-way concept lattice and its attribute reduction

Concept cognition and knowledge discovery under network data combine formal concept analysis with complex network analysis. However, in real life, network data is uncertain due to some limitations. Fuzzy sets are a powerful tool to deal with uncertainty and imprecision. Therefore, this paper focuses on concept-cognitive learning in fuzzy network formal contexts. Fuzzy object-induced network three-way concept (network OEF-concept) lattices and their properties are mainly investigated. In addition, three fuzzy network weaken-concepts are proposed. As the real data is too large, attribute reduction can simplify concept-cognitive learning by removing redundant attributes. Thus, the paper proposes attribute reduction methods that can keep the concept lattice structure isomorphic and the set of extents of granular concepts unchanged. Finally, an example is given to show the attribute reduction process of a fuzzy network three-way concept lattice. Attribute reduction experiments are conducted on nine datasets, and the results prove the feasibility of attribute reduction.