Solid Structure Research Articles

Wire-based friction stir additive manufacturing towards isotropic high-strength-ductility Al-Mg alloys

ABSTRACT The formation of eutectic Al-Mg2Al3 phases along the grain boundaries makes it difficult to improve the mechanical properties of high-magnesium-content aluminum alloys. Here, wire-based friction stir additive manufacturing(W-FSAM) was proposed as a novel solid-state additive manufacturing technology. The shearing, transport, and thermo-plasticisation processes of the deposited materials were achieved by a rotational tool and a stationary barrel. The original Mg2Al3 phases were refined and dissolved into the matrix and formed supersaturated solid solution structures. The refined grains with a diameter of 1.27 ± 0.64 μm were achieved through the dynamic recrystallization process. The components achieved isotropic mechanical properties due to the homogeneous equiaxed fine-grain structure. The ultimate tensile strength reached 415 ± 11 MPa with an elongation of 31.0 ± 2.0%, superior to the commercial 5xxx products. The enhanced strain hardening capacity was achieved by the suppressed emission of dislocations from grain boundaries and the interaction between the supersaturated solid solute atoms and mobile dislocation.

Pan-Draft: automated reconstruction of species-representative metabolic models from multiple genomes

The accurate reconstruction of genome-scale metabolic models (GEMs) for unculturable species poses challenges due to the incomplete and fragmented genetic information typical of metagenome-assembled genomes (MAGs). While existing tools leverage sequence homology from single genomes, this study introduces pan-Draft, a pan-reactome-based approach exploiting recurrent genetic evidence to determine the solid core structure of species-level GEMs. By comparing MAGs clustered at the species-level, pan-Draft addresses the issues due to the incompleteness and contamination of individual genomes, providing high-quality draft models and an accessory reactions catalog supporting the gapfilling step. This approach will improve our comprehension of metabolic functions of uncultured species.

Energy Harvesting Using Optimized ZnO Polymer Nanocomposite-Based 3D-Printed Lattice Structure

A 3D-printable polymer can provide an effective solution for developing piezoelectric structures. However, their nanocomposite formulation and 3D printing processability must be optimized for fabricating complex geometries with high printability. In the present study, we optimized the 3D-printable piezoelectric composite formulation for developing complex geometries by an additive manufacturing approach. The zinc oxide (ZnO) nanomaterial was synthesized by the hydrothermal method. The ZnO loading in the 3D-printed flexible resin was optimized to exhibit good interfacial adhesion and enable 3D printing. The lattice structure was fabricated to improve the piezoelectric response compared with the solid structure. The lattice structure block printed with 10 wt% ZnO showed a good piezoelectric response, with a linear increase in the generated output voltage for an increase in force. The maximum power density of 0.065 μW/cm2 was obtained under 12 N force at 1 Hz. The fabricated structure generated a peak–peak voltage of ~3 V with a foot heel strike.

Process Intensification via Structured Catalysts: Production of Sugar Alcohols

AbstractWith the aid of structured catalysts and reactors, such as monoliths, solid foams, and 3D printed structures, the limitations of conventional slurry and packed‐bed reactors can be surmounted. Multiphase mathematical models were presented for solid foam structures and the models were verified for the hydrogenation of arabinose, galactose, and xylose to the corresponding sugar alcohols. High product selectivities were obtained in batch and continuous experiments. Three kinetic models were considered: a competitive adsorption model, a semi‐competitive adsorption model as well as a non‐competitive adsorption model for sugar monomers and hydrogen. The models gave a good reproduction of the data, but the semi‐competitive adsorption model was the most plausible one because of the size difference between adsorbed sugar and hydrogen molecules.

Comparative analysis of tetravalent actinide Schiff base complexes: influence of donor and ligand backbone on molecular geometry and metal binding.

A series of isostructural early actinide AnIV complexes was synthesized in order to investigate the influence of a conjugated framework in the ligand backbone on An bonding. Therefore, the AnIV complexes [An(pyrophen)2] (An = Th, U, Np, and Pu) with the pure N-donor ligand bis(2-pyrrolecarbonylaldehyde)-o-phenylenediamine referred to as pyrophen, were synthesized and characterized. Solid state analysis via single-crystal X-ray diffraction (SC-XRD) reveals two sets of ligands binding in an almost orthogonal arrangement to the actinide center. For the larger actinides Th and U, the coordination sphere allows for additional coordination by a solvent molecule. Nuclear magnetic resonance spectroscopy (NMR) studies show the presence of highly symmetrical complexes in solution in good agreement with the solvent-free solid structures. While SC-XRD suggests mainly ionic binding, an analysis of paramagnetic NMR contributions and quantum chemical bond analysis hint towards significant covalency in the U, Np, and Pu compounds. This series of An complexes allowed for a thorough structural and theoretical comparison of a conjugated system to a closely related N-donor ligand (pyren)[1], as well as to the mixed N,O Schiff base ligands salophen (conjugated) and salen (non-conjugated).

Size-dependency and lattice-discreetness effect on fracture toughness in 2D crystals under antiplanar loading

AbstractFracture toughness is the material property characterizing resistance to failure. Predicting its value from the solid structure at the atomistic scale remains elusive, even in the simplest situations of brittle fracture. We report here numerical simulations of crack propagation in two-dimensional fuse networks of different periodic geometries, which are electrical analogs of bidimensional brittle crystals under antiplanar loading. Fracture energy is determined from Griffith’s analysis of energy balance during crack propagation, and fracture toughness is determined from fits of the displacement fields with Williams’ asymptotic solutions. Significant size dependencies are evidenced in small lattices, with fracture energy and fracture toughness both converging algebraically with system size toward well-defined material-constant values in the limit of infinite system size. The convergence speed depends on the loading conditions and is faster when the symmetry of the considered lattice increases. The material constants at infinity obey Irwin’s relation and properly define the material resistance to failure. Their values are approached up to $$\sim 15\%$$ ∼ 15 % using the recent analytical method proposed in Nguyen and Bonamy (Phys Rev Lett 123:205503, 2019). Nevertheless, the deviation remains finite and does not vanish when the system size goes to infinity. We finally show that this deviation is a consequence of the lattice discreetness and decreases when the super-singular terms of Williams’ solutions (absent in a continuum medium but present here due to lattice discreetness) are taken into account.

Modal analysis of the 63 Square Building in Seoul, South Korea and its impact of subsidence and soil-structure interactions (SSI)

We conduct vibration analyses of 63 Building in Seoul, South Korea, using modal analysis and finite element modeling. The building is modeled as a solid structure having the shape of the real structure and with total weight and stiffness consistent with those of the real building. To better understand the fundamental periods of vibration of this structure and the associated mode shapes, we also consider structures with simplified geometry and perform modal analyses of them.

Advances in Multiscale Modeling and Mechanical Properties Characterization of 3D‐Braided Composites

The 3D‐braided composites have been widely used in aerospace and other fields due to the excellent mechanical properties, designability, and resistance to delamination. Accurately analyzing and evaluating mechanical properties of braided composite structures is the key, which successfully designs related structural components. However, 3D‐braided composites have complex internal meso–microscopic structures, and directly establishing a solid structure model to predict mechanical behavior poses certain challenges. The multiscale research methods are a type of approach that studies the cross‐scale structural characteristics at macro–meso–microscopic scales and couples relevant scales into a whole. Its emergence provides the possibility for evaluating the overall structural performance of 3D‐braided composites. In this article, first, the multiscale analysis models of 3D‐multidirectional‐braided composites are reviewed, and then the theoretical and numerical research progress on the static and dynamic multiscale mechanical performance of regular components of 3D‐braided composites is summarized. In addition, due to the distortion and variation of geometric shapes of 3D‐braided composites on the meso–microscopic structure; therefore, also in this article, the research progress on multiscale mechanical performance characteristics of special‐shaped components is summarized. Finally, the key problems in the multiscale research of 3D‐braided composites are presented.

An interesting aggregation induced red shifted emissive and ESIPT active hydroxycoumarin tagged symmetrical azine: Colorimetric and fluorescent turn on–off–on response towards Cu2+ and Cysteine, real sample analysis and logic gate application

We report a newly synthesized 7-diethylamino-4-hydroxycoumarin tagged symmetrical azine derivative (SHC), with an interesting color transformation from yellowish green to orange via aggregation induced red shifted emissive (117 nm) feature in THF-H2O mixture. Interestingly, the single crystal X-ray analysis of this molecule demonstrates that two hydroxycoumarin moieties were present in azine unit, among them one of the coumarin units was exist as enol form and another one transferred to keto form via ground state proton transfer reaction. The optical responses of the compound in different solvents exposed the observation of dual emissive bands which corresponds to the presence of ESIPT phenomenon in SHC molecule. Further, this characteristic was confirmed by absorption, emission, solid state structure and time resolved fluorescence decay measurements. Furthermore, the fluorophore, SHC was exploited as a colorimetric and turn on–off–on fluorescent probe for detection of Cu2+ ions and Cysteine (Cys). The 1:1 binding ratio of the probe with Cu2+ and Cys with SHC-Cu2+, was established via Job plot analysis, mass spectral technique and the DFT calculations. The probe, SHC was employed for the detection of copper ions in the environmental real water samples. Finally, the reversible fluorescent turn on–off–on character of the probe, SHC was established to construct the IMPLICATION logic gate application.

Classification of solid and liquid structures using a deep neural network unveils origin of dynamical heterogeneities in supercooled liquids

As the temperature decreases, the dynamics of supercooled liquids significantly slow down and become increasingly heterogeneous in space. Many previous studies have found that static structures also become heterogeneous and are spatially correlated with the dynamical heterogeneity. However, there are still debates on whether the dynamical heterogeneity is controlled by the structures, and which structural order parameters should be used to describe the structural heterogeneities (if exist) in amorphous systems. The appropriate order parameter depends on the specific details of the system and needs to be determined for each system. To address this difficulty, here, we use a machine-learning-based method that was trained solely by the static structures. This method combines convolutional neural networks and gradient-weighted class activation mapping, providing interpretable characteristic structures, which can quantify the degrees of liquid-like and solid-like structures in every local part of the system. We apply this method to a canonical glass-forming system and demonstrate that particles in the liquid-like structures are mobile, while those in the solid-like structures are immobile. The present work develops a novel approach to accurately characterize amorphous structures, which will be particularly useful for systems where appropriate structural order parameters have not yet been identified.

Improving acoustic absorption modeling of additively manufactured microperforated panels through kriging-based approaches

Microperforated panels (MPPs) have emerged as good acoustic absorbers, with the Maa model being commonly utilized for predicting their acoustic absorption and impedance. However, discrepancies arise when applying this model to MPPs fabricated through additive manufacturing. Additive manufacturing offers design flexibility, but it challenges traditional acoustic models by not achieving ideal geometric characteristics. For instance, non-circular perforations resulting from the additive manufacturing, deviate from the perfect circular shape assumed in the Maa model. This non-ideal geometry poses challenges in predicting MPP acoustic absorption, particularly at lower frequencies and in wideband scenarios. Microscopic examinations reveal microporosity within panel solids, adding complexities not usually accounted for by models assuming a solid structure around perforations. This study investigates the observed disparity between Maa model predictions and experimental results due to manufacturing defects, microporosity within the MPPs and panel vibration. We address these challenges by introducing Kriging, a spatial interpolation technique, to refine the absorption model. The Kriging model demonstrates remarkable agreement with experimental data, offering a more accurate representation of the acoustic performance of additively manufactured MPPs. The proposed methodology not only contributes to advancing the understanding of acoustic absorption in MPPs but is also promising for optimizing their performance in real-world applications.

Novel Chiral Self-Assembled Nano-Fluorescence Materials with AIE Characteristics for Specific Enantioselective Recognition of L-Lysine.

In this paper, two aggregation-induced emission (AIE) chiral fluorescent materials, S-1 and S-2, were synthesized. The two materials are based on BINOL and H8-BINOL backbones, respectively, and large electron-absorbing groups are attached to the chiral backbones through the Knoevenagel reaction. At the same time, the CD signals of these two chiral fluorescent materials are gradually weakened (fw gradually increases) as they continue to aggregate. However, S-2 underwent a flip-flop from a negative to positive chiral CD signal at fw ≥ 90. And both materials also showed significant enantioselective recognition of lysine, demonstrating their potential as novel chiral fluorescent probes. Among them, the enantioselective fluorescence enhancement ratios (ef) of S-1 and S-2 for lysine were 10.0 and 10.3, respectively, while different degrees of blue shifts were produced by the ICT mechanism during the recognition process. In addition, the self-assembled morphology of the two nanomaterials is different; S-1 comprises hollow-core vesicles that are more likely to aggregate to form larger self-assembled vesicles, whereas S-2 is a solid block structure. When L/D-lysine was added alone, the morphology of S-1 was more distinctly different compared to S-2. With the addition of L-lysine, S-1 was dispersed and regularly spherical, whereas with the addition of D-lysine, S-1 itself remained in the form of aggregated large vesicles. This suggests that both S-1 and S-2 are important in the fields of chiral optics, chiral recognition, and nanoscale self-assembly.

Topology Optimization of Functionally Graded Structure for Thermal Management of Cooling Plate

The fast charge and discharge of a battery will significantly increase the overall temperature and thermal difference of the battery, which will further affect the working performance and safety of the battery. Therefore, a heat–fluid coupling topology optimization pipeline for developing radiation performance of the cooling plate is presented to ensure the thermal homogeneity of the battery in this paper. First, the Brinkman penalty model is utilized to construct the solid and fluid structures. Then, a local volume constraint is introduced to create the lattice structure to reduce the temperature difference of the cooling plate. Furthermore, a functionally graded lattice structure via a variable influence radius is presented to improve the radiation performance of the cooling plate when the thermal load is uneven. Numerical experiments are carried out to evaluate the performance of the presented methods on the optimization of the cooling plate, which indicates that the designed cooling plate by the proposed method improves the radiation performance when compared against a traditional straight channel and a SIMP-based optimal design.

An integrated approach combining experimental, informatics and energetic methods for solid form derisking of PF-06282999

The landscapes of observed and predicted three-dimensional crystal packing arrangements of small-molecule drug candidates can be complex. The possible appearance of a more thermodynamically stable solid form during drug development has led to the digital workflow of informatics-based risk assessments, named a Solid Form Health Check. Herein, we describe the use of a combined approach consisting of experiments, informatics together with energetic calculations in analysis of four competing polymorphs of PF-06282999, a myeloperoxidase (MPO) inhibitor with conformational flexibility and multiple plausible hydrogen bond networks. This combined approach offered a comprehensive understanding of the solid form structure, properties, and performance, ensuring robust solid form derisking and selection.

Natural synergy: Oleanolic acid-curcumin co-assembled nanoparticles combat osteoarthritis

Curcumin (Cur) is a natural polyphenol that is one of the most valuable natural products. However, its use as a functional food is limited by low water solubility, chemical instability and poor bioavailability. In this study, a supramolecular co-assembly strategy was used to construct an oleanolic acid-curcumin (OLA-Cur) co-assembly composite nano-slow-release treatment system. As a co-assembled compound, OLA is a widely present pentacyclic triterpenoid compound with multiple biological activities in the plant kingdom, which is expected to jointly alleviate the damaging effects of papain-induced mouse osteoarthritis model. The OLA-Cur NPs shows the solid core-shell structure, which can effectively improve the water solubility of Cur and OLA, and has good stability and sustained release characteristics. The analysis results show that the two compounds are mainly assembled through hydrogen bonding interactions, hydrophobic interactions, and π - π stacking interactions. The OLA-Cur NPs can inhibit the release of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β induced by LPS in RAW264.7 mouse macrophages, promote the secretion of anti-inflammatory cytokine IL-10, and improve the oxidative stress index of hydrogen peroxide induced human rheumatoid arthritis synovial fibroblasts. In addition, it has a certain improvement effect on cartilage and subchondral bone damage in mouse osteoarthritis models. These findings suggest that constructing co-assembled composite nanoparticles based on pure natural compounds may break through the limitations of a variety of important nutritional ingredients in functional foods.

Numerical investigation on machining of additively manufactured CFRP composite with different build orientations and layer widths

Additive manufacturing (AM) is now a widely researched manufacturing technology in the past two decades to adopt in industry for its added advantage of customization and adopting complex geometries with comparatively low buy-to-fly ratio. Carbon fiber reinforced polymer (CFRP) composite has found applications in different high-performance industries for its greatest benefit of high strength-to-weight ratio. Additive manufacturing of CFRP composite (AM-CFRP) opens up the possibility of enhancing mechanical strength using different printing orientations and enables producing complex shapes maintaining sustainable manufacturing perspective. However, Limitation of AM parts of having surface irregularities and questionable dimensional accuracies. To use AM-CFRP parts in high precision assembly or industrial applications, post processing machining is often required to meet the customers’ specification of geometrical tolerances and acceptable surface finish. In this study, the influence of AM parameters on machinability of AM-CFRP composite has been evaluated using finite element analysis (FEA) based numerical simulation. The slot milling operation was simulated with a tungsten carbide end milling tool and AM-CFRP workpiece with four different printing directions, i.e., 0°-90°, 45°-135°, 0°-90°-45°-135°, two different layer widths, i.e., 50 µm and 100 µm, and two in-fill patterns, i.e., solid and perforated structures. The machinability of the 3D printed CFRP has been analyzed based on cutting forces, stress at first contact and maximum stress generation, and temperature increases at the interface during slot milling of AM-CFRP under different AM parameters. Evolution of failure mechanisms of AM-CFRPs under various machining conditions, such as, delamination, matrix rupture etc., have been discussed and chip and burr formation mechanisms have been analyzed. Finite Element analysis (FEA) package ABAQUS/Explicit was used to model 3D micro slot milling operation of AM-CFRP workpiece with appropriate damage and constitutive models, such as, damage initiation, progression and cohesion in adjacent passes and layers.

In silico studies of thiazole derivative towards its potential use against SARS-CoV-2: An intuition from an experimental and computational approach

The N-(4-methoxyphenyl)-4-phenylthiazole-2-carboxamide (TT7) obtained via cyclization of methyl 2-((4-methoxyphenyl)amino)-2-oxoethanedithioate with ɑ-haloketone and then characterized by 1H-NMR and 13C-NMR spectroscopy, and single crystal X-ray diffraction method. Weak intermolecular interactions like C-H...O, C-H...π, C-O...π, and π...π interactions help to stabilize the compound TT7. The weak interactions formed in the solid structure of the compound TT7 were meticulously investigated using theoretical approach like Hirshfeld surface analysis using crystallographic information file (.cif). Further, the density functional theory calculations have been performed to obtain the optimized geometry of the structure, and to explore the electronic properties of the molecule. The charge distribution on the molecular surface is analyzed by the molecular electrostatic potential (MEP) map. QTAIM and RDG analyses were done to explore the weak interactions (intramolecular) in the compound TT7 in the gaseous phase. The compound TT7 displayed good in silico results against SARS-CoV-2 main protease. Molecular docking study on SARS-CoV-2 virus major protease (PDB IDs: 6LZE and 6LU7) shows higher docking scores. Molecular dynamics simulations confirmed the inhibitory action of the newly synthesized compound (TT7). The binding free energy and contributed energies were determined using the MM-GBSA technique. The 6LU7-ligand complex has the highest binding free energy, with considerable contributions from covalent and van der Waals interactions.

A vine-copulas based multi-sensor fusion structural damage monitoring method and its application in dam engineering

As a civil engineer that is susceptible to the mechanism of slow and continuous deterioration, the dam must detect damage according to the static data of the arranged sensors, which is an important issue in structural health monitoring. Due to the characteristics of huge solid structures, damage with a slight degree and small range usually does not cause significant changes in the monitoring data of a single sensor. Therefore, it is difficult to effectively detect local damage by traditional monitoring methods that establish operating warning values for a single sensor. Currently, there have been some approaches to fuse sensor information that consider correlations between multiple sensors as well as the overall operational behavior of the dam. However, their objectives are focused on improving the accuracy of response variable prediction models without addressing the local damage identification aspect. In this study, we apply the Vine-Copula model for the first time in a multi-sensor information fusion dam damage detection method based on static monitoring data. In this way, it improves the sensitivity of local damage identification for huge solid structures. A prediction model is fitted with the measuring data of each sensor to obtain the residual series. Then the joint probability distribution of the multidimensional residuals is acquired by constructing the Vine-Copula model. Finally, the joint cumulative distribution function value is used as an alarm limit to determine whether the structure has an abnormal damage condition. The effectiveness and accuracy of the proposed method were demonstrated in both a numerical arch dam simulating local damage and an actual rockfill dam engineering with cracks at the crest.

Impact of warming and acidification of the Mediterranean Sea on statolith formation of the scyphozoan jellyfish Rhizostoma pulmo Macri (1778)

Ocean warming and acidification negatively affect organisms and biogeochemical cycles. To date, emphasis has been placed on the study of the impact on the structures of calcifying species; however, there is limited knowledge about the influence of the increase of these two variables on the solid structures of non-calcifying species as jellyfish. Here, we study the effects that the increase of temperature and acidity would cause on the statoliths of newly released ephyrae of the Mediterranean jellyfish Rhizostoma pulmo. Six combinations of temperature and PCO2 (18, 24 and 30ºC with a PCO2 of 500 and 1000 ppm each), according to the projections of the SSP5-8.5 (IPCC, 2021) scenario for the year 2100, were applied during 32 days to different groups of polyps randomly selected. Statoliths of the released ephyrae were counted and their size was measured. Our results show that, even though neither temperature nor PCO2 increase exerted a representative effect on the amount of statoliths synthesized in newly released ephyra from R. pulmo, it did exert an impact on the size of these structures: warming led to the formation of larger statoliths, while the rise in PCO2 induced the production of smaller structures. Under the simultaneous increase of both variables, acidification attenuated the effects of temperature, but still slightly larger statoliths were synthesized. The size differences observed in these structures could negatively impact the equilibrium system of this jellyfish species, potentially affecting its ability to survive.

Controllable preparation of hexanitrostilbene (HNS) microspheres with multi-cavity structure to enhance safety and combustion performance

Controlling the structure to meet the demand for high-energy, low-sensitivity energetic materials in modern military and civilian applications is an effective method. In this study, hexanitrostilbene (HNS) microspheres with a multi-cavity structure were prepared using nitrocellulose (NC) and fluororubber (F2604) as binders via microjet droplet technology. The effects of flow rate, receiving liquid temperature, and suspension concentration on the morphology, particle size, and cavity of the HNS microspheres were investigated. Furthermore, the impact of the multi-cavity structure on the microspheres' specific surface area, dispersibility, thermal properties, safety performance, and combustion performance was studied. Results showed that the multi-cavity HNS microspheres retained the raw materials' crystal structure while exhibiting improved dispersibility, higher activation energy, and shorter ignition delay. Moreover, the multi-cavity structure outperformed the solid structure in terms of specific surface area, safety performance, and combustion performance. This study opens up a new direction for the preparation of multi-structured energetic microspheres.