Basal Plane Research Articles

Thermal–structural response and life prediction of lattice regenerative cooling thrust chambers in liquid rocket engines based on a simplified viscoplastic model

With advances in aerospace technology, the reusability of liquid rocket engines has become the focus of considerable research interest. Traditional channel-type regenerative cooling thrust chambers often experience plastic deformation and microcracks, which limit their lifespan. This study proposed a novel lattice regenerative cooling thrust chamber using a simplified viscoplastic model and ABAQUS finite element software to simulate thermal–structural responses under different pressure conditions. The lattice structure not only enhanced the cooling efficiency and reduced the structural weight but also mitigated the plastic deformation and high-temperature creep of the inner wall. At an inner-wall temperature of 820 K, creep damage was significant. Compared to that of traditional chambers, the lattice structure of the proposed chamber exhibited different mechanical behavior and failure modes, with a more uniform stress distribution and initial failure occurring at the lattice nodes. The proposed design avoided the “doghouse” effect evident in traditional chambers, achieving an inner-wall lifespan of up to 202 cycles, a 359 % improvement. The high design flexibility of the lattice structure in the cooling channels enabled enhanced thrust chamber longevity. The study results provide new insights and technical support for next-generation liquid rocket engine designs.

Strengthening cationic repulsion on graphene oxide membrane to boost water desalination

BackgroundAs a hydrophilic two-dimensional material with oxygen-containing groups on its basal planes, graphene oxide (GO) has been used for the fabrication of GO-based membranes to purify/desalinate water. However, promoting salt rejection of GO-based membranes is challenging while maintaining high water permeability. MethodsFirst, the mercaptoethylamine-modified Ag NWs (Ag-MA) were prepared by mixing Ag NWs and MA to form Ag—S bonds. Then, Ag-MA was deposited on the GO membrane under externally assisted filtration to achieve the GO/Ag-MA membrane, which ensures the well-stacking of GO sheets and the even coating of GO membrane. Therefore, the delicately fabricated membrane possesses great electropositive cations and high swelling-tolerance in water solution. Significant findingsWe found that a high electrostatic repulsive interaction between the amino group and metal cations in GO/Ag-MA membrane aided the promotion of rejection rates, which was up to 75 % for both K+ and Mg2+, surpassing that of the previously reported values. This work highlights a new approach for enhancing the electrostatic repulsion with metal cations near the surface/interface of GO-based membranes and their application in the development of water desalination and purification.

Effect of orbital hybridization inspired tessellation strategy on the mechanical properties of lattice structures

The work presents a noble orbital hybridization-inspired tessellation approach for lattice structures, which may modify the characteristics of a lattice. The strategy organizing lattice unit cells according to sp, sp2, sp3, and sp3d2 hybridization patterns. Material extrusion (MEX) was employed to manufacture the tessellated structures, and it was investigated using static and dynamic loads. The sp3-inspired tessellation displayed the greatest energy absorption and revealed two separate failure modes: layer-wise and layer-coupled cell failure. The sp3-inspired tessellated structure displayed the greatest modulus and plateau stress. The current approach was effectively employed to modify the static and dynamic mechanical characteristics of lattice unit cells.

Topological flat band with higher winding number in a superradiance lattice

A five-level M-type scheme in atomic ensembles is proposed to generate a one-dimensional bipartite superradiance lattice in momentum space. By taking advantage of this tunable atomic system, we show that various types of Su-Schrieffer-Heeger (SSH) model, including the standard SSH and extended SSH model, can be realized. Interestingly, it is shown that through changing the Rabi frequencies and detunings in our proposed scheme, there is a topological phase transition from topological trivial regime with winding number being 0 to topological non-trivial regime with winding number being 2. Furthermore, a robust flat band with higher winding number (being 2) can be achieved in the above topological non-trivial regime, where the superradiance spectra can be utilized as a tool for experimental detection. Our proposal would provide a promising approach to explore new physics, such as fractional topological phases, in the flat bands with higher topological number.

Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights

Effective surface functionalization of carbon nanomaterials plays a crucial role in various applications. We investigated the impact of edges on surface functionalization and stability of oxygen-modified carbon materials using a combination of experimental techniques and Density Functional Theory (DFT) insights. Graphenic paper, highly oriented pyrolytic graphite (HOPG), and graphenic flakes were employed as model systems, with oxygen plasma treatment (generator power 100 W, oxygen pressure 0.2 mbar, exposure time 6 – 300 s) serving as the modification method. Surface morphology and chemical composition were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The results revealed the introduction of oxygen functional groups on the investigated carbon surfaces (up to 20 at % by XPS) whereas; the structural integrity of the materials remained intact upon plasma modification (SEM, Raman). Work function was used as a sensitive parameter for monitoring the surface changes (increase by ∼1.4 eV, 1.3 eV, and 1 eV for graphenic paper, HOPG, and graphenic flakes, respectively) while time-dependent measurements revealed distinct kinetic processes governing the decay of functionalization, highlighting the role of surface defects in post-plasma processes. DFT calculations provided molecular-level insights into the surface processes, elucidating the mechanisms underlying the diffusion of hydroxyls, their recombination, and water desorption. Since the calculated activation barrier for recombination on basal graphenic planes (∼1.0 eV) and edges (∼5.5 eV) are distinctly different, it can be thus concluded that the persistent functionalization is due to the surface edges. Our findings contribute to a deeper understanding of surface modification processes of carbon materials and offer rationales for the design of advanced functional nanomaterials with tailored surface properties.

Insightful interpretation of the unique stacking faults of Na3Ni2SbO6 through cobalt doping for enhanced sodium-ion battery performance

The O3-Na3Ni2SbO6 compound, with its hexagonal honeycomb cationic ordering, is a promising sodium-ion battery (SIB) cathode due to its phase transition steps and high average voltage. In this study, various concentrations of cobalt (Co) are doped into Na3Ni2SbO6 to replace nickel (Ni), increasing disorder within the transition metal layers. Co doping introduced specific stacking faults along the c-axis direction, resulting in an ambiguous configuration of Sb/Ni(Co) within each transition metal layer, while maintaining the honeycomb order. This disorderly arrangement optimized the electronic structure and reduced the energy barrier for reactions. Na3Ni1.6Co0.4SbO6 exhibited superior performance, with a higher initial discharge capacity (137.8 mAh g-1 at 0.1 C) and better rate performance (87 mAh g-1 at 5 C) compared to Na3Ni2SbO6 (113.6 mAh g-1 at 0.1 C, 74 mAh g-1 at 5 C), including improved long-term cyclic stability. The findings demonstrate that electrochemical performance can be significantly enhanced through atomic layer stacking disorder and the Na coordination environment, which is influenced by Na ion extraction and insertion, resulting in more gradual and smaller variations in lattice parameters, electronic structure, and crystal defects. This study provides a foundation for future designs of sodium-ion battery cathode materials with improved performance.

Activating S-inert sites on ReS2 basal plane via Mo doping to boost electrochemical hydrogen evolution reaction

Activating S-inert sites on ReS2 basal plane via Mo doping to boost electrochemical hydrogen evolution reaction

Shock Response of Sandwich Panels with Additively Manufactured Polymer Gyroid Lattice Cores

This work evaluates the shock response of sandwich structures with gyroid lattice cores made from Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), and Thermoplastic Polyurethane (TPU) using shock tube experiments coupled with high-speed photography and digital image correlation (DIC). The study found that gyroid lattice structures exhibit high energy absorption capacity and good structural integrity under shock loading, making them suitable for high strength-to-weight ratio and energy absorption applications in aerospace and defense industries. The sandwich panel with a TPU-core structure exhibited the highest deformation under shock loading, with a maximum deflection of approximately 6mm, followed by ABS at 0.9mm and PLA at 0.82mm. Under shock loading, the sandwich panel with TPU gyroid core exhibited the highest specific deformation energy (0.146J/g), which is consistent with its flexibility, though it remained in the same general order as ABS (0.104J/g) and PLA (0.070J/g). Interestingly, the specific total energy of the TPU gyroid core sandwich, while the lowest at 39.310J/g, was still relatively close to ABS (54.098J/g) and PLA (52.620J/g), despite the substantial difference in inherent stiffness of TPU compared to ABS and PLA. This suggests that while TPU's stiffness is much lower compared to PLA and ABS, its total energy absorption capability in gyroid form is not as drastically reduced, indicating the importance of geometry and mass distribution within the gyroid structure. Overall, the results of this study highlight the importance of careful design and optimization of these structures to utilize their unique properties fully.

Graphene: Study in Electronic Structure, Superconductivity and Potential in Quantum Information Sciences

Graphene, a two-dimensional lattice of carbon atoms, exhibits remarkable electronic properties due to its Dirac-like electronic excitations. This paper reviews the elementary electronic properties of graphene, including the tight-binding model for single-layer graphene and the band structure formation. The tight-binding Hamiltonian provides a fundamental understanding of graphene’s linear energy dispersion near the Dirac points, leading to unique phenomena such as massless Dirac fermions and chiral tunneling. We explore the potential of superconductivity in graphene using BCS theory. We find that BCS theory cannot explain superconductivity in graphene and its forms. This is in contradiction with the discovery of unconventional superconductivity in twisted bilayer graphene (TBG). The study further explores the potential application of bilayer graphene quantum in quantum information sciences, highlighting the development of states with relaxation times exceeding 500 ms. These valley states, arising from the hexagonal lattice structure, can be used to encode information as robust valley qubits for fault-tolerant quantum computing

Supramolecular Crystals based Fast Single Ion Conductor for Long‐Cycling Solid Zinc Batteries

AbstractThe solid polymer electrolytes (SPEs) used in Zn‐ion batteries (ZIBs) have low ionic conductivity due to the sluggish dynamics of polymer segments. Thus, only short‐range movement of cations is supported, leading to low ionic conductivity and Zn2+ transference (tZn2+). Zn‐based supramolecular crystals (ZMCs) have considerable potential for supporting long‐distance Zn2+ transport; however, their efficiency in ZIBs has not been explored. The present study developed a ZMC consisting of succinonitrile (SN) and zinc bis (trifluoromethylsulfonyl) imide (Zn(TFSI)2), with a structural formula identified as Zn(TFSI)2SN3. The ZMC has ordered three‐dimensional tunnels in the crystalline lattices for ion conduction, providing high ionic conductivities (6.02×10−4 S cm−1 at 25 °C and 3.26×10−5 S cm−1 at −35 °C) and a high tZn2+ (0.97). We demonstrated that a Zn‖Zn symmetrical battery with ZMCs has long‐term cycling stability (1200 h) and a dendrite‐free Zn plating/stripping process, even at a high plating areal density of 3 mAh cm−2. The as‐fabricated solid‐state Zn battery exhibited excellent performance, including high discharge capacity (1.52 mAh cm−2), long‐term cycling stability (83.6 % capacity retention after 70000 cycles (7 months)), wide temperature adaptability (−35 to 50 °C) and fast charging ability. The ZMC differs from SPEs in its structure for transporting Zn2+ ions, significantly improving solid‐state ZIBs while maintaining safety, durability, and sustainability.

Uranium-Mediated Thiourea/Urea Conversion on Chelating Ligands

2,6-Dipicolinoylbis(N,N-dialkylthioureas) and H2LR2 react with uranyl salts and a supporting base (e.g., NEt3) under formation of monomeric or oligomeric complexes of the compositions [UO2(LR2)(solv)] (solv = donor solvents) or [{UO2(LR2)(µ2-OMe)}2]2–. In such complexes, the uranyl ions are commonly coordinated by the “hard” O,N,O or N,N,N donor atom sets of the central ligand unit and the lateral sulfur donor atoms remain uncoordinated. Their individual structures, however, depend on the reaction conditions, particularly on the equivalents of NEt3 used. An unprecedented, selective hydrolysis of the uranium-coordinating bis(thioureato) ligands results in an S/O donor atom exchange at exclusively one thiourea side-arm, when an excess of NEt3 is used. The resulting trimeric uranyl complexes are isolated in fair yields and have a composition of [(UO2)3(L2Et2)2(µ2–OR)(µ3-O)]–. H2L2Et2 represents the newly formed 2,6-dipicolinoyl(N,N-diethylthiourea)(N,N-diethylurea) and R = H, Me, or Et. {L2Et2}2– binds to the uranyl units via the pyridine ring, the dialkylurea arm, and the central carbonyl groups, while the thiourea unit remains uncoordinated. The central cores of the products consist of oxido-centered triangular {(UO2)3O}4+ units. The observed reactivity is metal-driven and corresponds mechanistically most probably to a classical metal-catalyzed hydrodesulfurization. The hydrolytic thiourea/urea conversion is only observed in the presence of uranyl ions. The products were isolated in crystalline form and studied spectroscopically and by X-ray diffraction. The experimental findings are accompanied by DFT calculations, which help to understand the energetic implications in such systems.

Plasmon–Exciton–Polariton Condensation in Organic Semiconductor‐Covered Plasmonic Lattices

AbstractExciton–polariton condensates featuring collective coherence and large nonlinearities are promising for advancing coherent light sources and functional devices. Nevertheless, their reliance on planar cavities with large lateral device footprints and mode volumes hinders device integration. Plasmon–exciton–polaritons (PEPs), arising from the strong coupling between excitons and plasmons, provide an intriguing platform to explore emergent polariton condensation at the nanoscale due to their ultrasmall mode volumes in metal nanoparticles. However, the substantial radiative and Ohmic losses in metals hamper PEPs condensation, particularly in the short wavelength range (<600 nm). Here, a method is proposed to address metal losses by integrating organic semiconductor neat films onto plasmonic lattices. The use of organic semiconductors with large transition dipole moment and low non‐radiation loss enables efficient coupling between massive excitons and lattice plasmons, leading to high‐density PEPs. This ensures a macroscopic number of polaritons populating the low‐lying band edge at relatively low fluences to obtain bosonic stimulation, resulting in PEP condensation. By tailoring the band structures of plasmonic lattices, the condensation of PEPs are further manipulated into different energy states. These findings offer valuable insights for the design of PEP systems and all‐optical polaritonic devices.

Evaluation of clinical effects of Advansync 2 fixed functional appliance in skeletal Class II malocclusion: A retrospective cephalometric study

To evaluate the treatment effects of AdvancSync 2 in patients of skeletal Class II malocclusion in selected skeletal, dental, soft tissue and airway parameters. Pretreatment and post-functional lateral cephalograms of 12 patients (06 males and 06 females with mean age of 14.25+0.75) with skeletal Class II malocclusion treated using AdvanSync 2 were evaluated. Paired t-test and Wilcoxon rank-sum intraclass correlation (ICC) test results were calculated.Statistically significant changes were found in skeletal parameters ofSNB, Wits, maxillo-mandibular differential, Björk’s sum, basal plane angle, Sn-GoGn, lower anterior facial height (LAFH), Na-perp-Pog. Changes in dental parameters U1-NA (angular and linear), L1 to NB (angular and linear), U1-SN angle, IMPA, Inter-incisal angle, L1 to A-Pog and U1 to A-Pog were also observed to be statistically significant at T1. Soft tissue skeletal convexity and nasolabial angle improved significantly post treatment, while, statistically significant change was observed only in posterior pharyngeal airway space among the chosen cephalometric airway parameters.Treatment with AdvanSync 2 corrected the Class II malocclusion by producing skeletal and dentoalveolar changes. Soft tissue facial convexity and nasolabial angle improved with treatment. Further, linear dimension of the posterior pharyngeal airway space showed significant improvement with AdvanSync 2 therapy.

An Effective Alternative to the Open Trench Method for Mitigating Ground-Borne Environmental Body Waves: Corrugated Cardboard Boxes Reinforced with Balsa Wood

This research develops and evaluates a recyclable corrugated cardboard vibration isolation box reinforced with balsa wood as an alternative to traditional open trench methods for mitigating ground-borne environmental body waves. This study includes designing and testing scaled prototypes, laboratory analyses, prototype fabrication, and full-scale field experiments. In soft ground conditions, ensuring slope stability during deep excavations is a key engineering challenge for open trenches. For this purpose, scaled prototypes were subjected to laboratory tests to assess the resistance of the wave barrier’s wall surface. Numerical analyses were also conducted to evaluate the strength of the internal lattice structure under various loads. A prototype was fabricated for on-site experiments simulating real-world conditions. Field experiments evaluated the vibration isolation performance of the proposed barrier. Accelerometer sensors were strategically placed to gather data, analyzing ground surface vibrations for free field motions to assess the vibration shielding efficiency of both the open trench method and the corrugated vibration isolation box, with and without Styrofoam infill. This study concludes that the recyclable corrugated vibration isolation box is a viable alternative, offering comparable or improved vibration isolation efficiency in soft soil conditions while promoting environmental sustainability using recyclable materials.

Site-Specific Stochastic Rates and Energetics of Ag Nucleation on Highly Ordered Pyrolytic Graphite.

Nucleation is a fundamentally important step in electrochemical phase transition reactions, e.g., in electrodeposition, which is pertinent for emerging battery technology, nanoparticle synthesis, and many industrial processes. Surface defects have been suggested to enhance nucleation rates. However, directly quantifying the nucleation rates at specific surface sites is challenging due to the ensemble averaging effect in bulk measurements. Herein, we report the measurement of rates and energetics of electronucleation across the model surface of highly oriented pyrolytic graphite (HOPG). Specifically, scanning electrochemical cell microscopy (SECCM) is used to confine the nucleation spatially in the nanoscale cell, allowing one nucleation event to be measured at one time. The scanning capability further allows the mapping of Ag nucleation at the step edge vs basal plane. A stochastic model is developed to extract the nucleation rate and energetics from voltammetric experiments. We observed a ∼57 mV difference in the median nucleation overpotential between the step edge and basal plane, corresponding to a ∼12 kJ mol-1 difference in the nucleation energy barrier. The voltammetric method to measure the nucleation rate explored here can be extended to understand the heterogeneity of nucleation rates in other electrochemical nucleation systems, e.g., metal anode batteries.

Fabrication of dense Cf/SiC ceramic matrix composites using 3D printing and PIP with short carbon fibre as a toughening material

ABSTRACT To achieve weight reduction, toughness enhancement, and the fabrication of complex structures in SiC composites, a combination of SLS and PIP processes was used. Silicon carbide powder served as the matrix material, while short carbon fibres were used for toughening, resulting in dense Cf/SiC ceramic matrix composites. The effects of varying carbon fibre sizes and contents on the microstructure and mechanical properties of Cf/SiC composites were examined. Results indicated that adding 8% carbon fibre increased the fracture toughness of Cf/SiC composites by 33.33%. Further increases in carbon fibre content showed minimal effects on fracture toughness. Based on experimental results and finite element simulations, toughening mechanisms, including fibre pull-out, fibre debonding, and crack deflection, were further elucidated. Consequently, Cf/SiC composites with complex structures, such as turbine specimens and lattice structures, were successfully fabricated.

Cocrystallization Enables Ensitrelvir to Overcome Anomalous Low Solubility Caused by Strong Intermolecular Interactions between Triazine-Triazole Groups in Stable Crystal Form.

Ensitrelvir is a nonpeptide 3CL protease inhibitor used for coronavirus disease 2019 treatment. Four crystalline forms of ensitrelvir, metastable (Form I), acetonate (Form II), stable (Form III), and hydrate (Form IV), have been analyzed as pharmaceutical crystals. Their rank order of solubility is Form I > IV > III. Form III is the stable crystal with a significantly lower solubility than that predicted from its log P value of 2.7. Here, single-crystal structural analysis revealed strong intermolecular interactions between the triazine (acidic) and triazole (basic) groups of Form III not Forms I and IV. Multicomponent crystals were also designed to improve the solubility by altering the intermolecular interactions in Form III. Slurry conversion with equal molar ratios of ensitrelvir and fumaric acid successfully induced the formation of a novel cocrystal (Form V). Fumaric acid inhibited the triazine-triazole interactions, and dissolution of Form V was approximately 8- and 13-fold higher than that of Form III in pH 1.2 and 6.8 media, respectively. Furthermore, Form V exhibited an approximately 16-fold higher flux value than that of Form III. Therefore, alterations in intermolecular interactions via cocrystallization significantly enhance the dissolution and permeation of ensitrelvir.

In-Situ visual reconstruction of strut profiles in pulsed wire arc additive manufacturing of lattice structures

ABSTRACT The wire arc additive manufacturing (WAAM) process often results in geometric inaccuracies in the produced struts, highlighting the need for in-situ monitoring. Industrial cameras struggle to capture accurate images due to interference from arc light and metal radiation. This study introduces a real-time visual reconstruction method that leverages regions of interest (ROI) to enhance profile accuracy. Initially, the melt pool is analyzed and segmented from a series of frames to establish an initial strut profile. This profile then serves as the ROI for segmenting the solidified weld bead regions, yielding a more precise strut profile. Comparative analysis shows that the proposed method achieves a high Intersection Over Union (IOU) score of 0.911 and an Average Symmetric Surface Distance (ASD) error of 0.355 mm, demonstrating both accuracy and robustness. Additionally, the inclination angle and diameter are extracted from the reconstructed profiles.

Microstructural and mechanical properties study of various lattice structures of SS316L-CNTs nano composites fabricated through additive manufacturing

Abstract In this work, various lattice structures, such as FCC (face-centered), BCC (body-centered), GD (Gyroid), and BGD (bare gyroid (without CNTs)) with four different porosities (60%, 70%, 80%, and 90%), were prepared through the SLM (selective laser melting) additive manufacturing process. Stainless Steel (SS) 316L alloy was utilized as the base material, while 0.2 wt.% functionalized CNTs (Carbon Nanotubes) were employed as reinforcement. The uniform dispersion of CNTs was analyzed using FESEM, TEM, and Raman spectroscopy. The results indicated that the plateau stress increases with the addition of CNTs, as well as with relative density, whereas energy absorption increases with the addition of CNTs. However, with increasing relative densities, energy absorption nature changes from increasing to decreasing. The results showed that among all lattice structures formed with CNTs addition, the Gyroid lattice exhibited the highest plateau stress, while the BCC lattice exhibited the lowest plateau stress.

The \(s\)-Weak Order and \(s\)-Permutahedra I: Combinatorics and Lattice Structure

The \(s\)-Weak Order and \(s\)-Permutahedra I: Combinatorics and Lattice Structure