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Abaca fiber degradation in concrete owing to its alkaline nature decreases the strength of concrete. This research focuses on overcoming the degradation by alkaline treatment with sodium hydroxide (NaOH) to improve fiber performance. This study was completed with the extraction process of fiber, mechanical properties, micro-structural analysis of composite fiber concrete for both M30 and M40 grades, and durability performance if the fiber content, aspect ratio of fiber and molarities of Sodium Hydroxide were optimized using splitting tensile strength of the concrete matrix and it was found that the optimum percentage of fiber content was 1% at 12% alkali treatment. The composite concrete has achieved an increase of 2700 to 3100 kg m −2 in split tensile strength with treated abaca fibers compared to untreated fiber concrete. In addition, treated abaca fiber concrete provides better performance in mechanical and durability studies. The binding nature of fiber concrete is better than that of conventional concrete, which is evidenced in microstructural analysis. This study ultimately concluded that the treated abaca fiber composite concrete is a better alternative to commercially available untreated abaca fibers and other natural fibers.

Microstructural characterization and analysis is the foundation of microstructural science, connecting materials structure to composition, process history, and properties. Microstructural quantification traditionally involves a human deciding what to measure and then devising a method for doing so. However, recent advances in computer vision (CV) and machine learning (ML) offer new approaches for extracting information from microstructural images. This overview surveys CV methods for numerically encoding the visual information contained in a microstructural image using either feature-based representations or convolutional neural network (CNN) layers, which then provides input to supervised or unsupervised ML algorithms that find associations and trends in the high-dimensional image representation. CV/ML systems for microstructural characterization and analysis span the taxonomy of image analysis tasks, including image classification, semantic segmentation, object detection, and instance segmentation. These tools enable new approaches to microstructural analysis, including the development of new, rich visual metrics and the discovery of processing-microstructure-property relationships.

The cracking of screws made from medium-carbon cold heading steel for the electronic parking brake system was studied through the analysis of the microstructure and the systematic investigation of the whole process, and the corresponding improvement measures were proposed at last. Results showed that the cracks initiated at the root of the threads due to insufficient plasticity generated by the large pressure during thread rolling were the resource of the fracture, which was further extruded during the turning process, while the centering condition was not well. It was necessary to adjust the appropriate parameters of rolling pressure and rolling time to avoid heavy work hardening and also pay attention to the cleanness on the surface of the rolling plate or the wheel.

The aim of this study is to characterise the changes in mechanical properties and to provide a comprehensive micro-structural analysis of Harcourt granite over different pre-heating temperatures under two cooling treatments (1) rapid and (2) slow cooling. A series of uniaxial compression tests was conducted to evaluate the mechanical properties of granite specimens subjected to pre-heating to temperatures ranging from 25–1000 °C under both cooling conditions. An acoustic emission (AE) system was incorporated to identify the fracture propagation stress thresholds. Furthermore, the effect of loading and unloading behaviour on the elastic properties of Harcourt granite was evaluated at two locations prior to failure: (1) crack initiation and (2) crack damage. Scanning electron microscopy (SEM) analyses were conducted on heat-treated thin rock slices to observe the crack/fracture patterns and to quantify the extent of micro-cracking during intense heating followed by cooling. The results revealed that the thermal field induced in the Harcourt granite pore structure during heating up to 100 °C followed by cooling causes cracks to close, resulting in increased mechanical characteristics, in particular, material stiffness and strength. Thereafter, a decline in mechanical properties occurs with the increase of pre-heating temperatures from 100 °C to 800 °C. However, the thermal deterioration under rapid cooling is much higher than that under slow cooling, because rapid cooling appears to produce a significant amount of micro-cracking due to the irreversible thermal shock induced. Multiple stages of loading and unloading prior to failure degrade the elastic properties of Harcourt granite due to the damage accumulated through the coalescence of micro-cracks induced during compression loading. However, this degradation is insignificant for pre-heating temperatures over 400 °C, since the specimens are already damaged due to excessive thermal deterioration. Moreover, unloading after crack initiation tends to cause insignificant irreversible strains, whereas significant permanent strains occur during unloading after crack damage, and this appears to increase with the increase of pre-heating temperature over 400 °C.

π-Conjugated organic semiconductors have been explored in several optoelectronic devices, yet their use in molecular detection as surface-enhanced Raman spectroscopy (SERS)-active platforms is unknown. Herein, we demonstrate that SERS-active, superhydrophobic and ivy-like nanostructured films of a molecular semiconductor, α,ω-diperfluorohexylquaterthiophene (DFH-4T), can be easily fabricated by vapour deposition. DFH-4T films without any additional plasmonic layer exhibit unprecedented Raman signal enhancements up to 3.4 × 10 3 for the probe molecule methylene blue. The combination of quantum mechanical computations, comparative experiments with a fluorocarbon-free α,ω-dihexylquaterthiophene (DH-4T), and thin-film microstructural analysis demonstrates the fundamental roles of the π-conjugated core fluorocarbon substitution and the unique DFH-4T film morphology governing the SERS response. Furthermore, Raman signal enhancements up to ∼10 10 and sub-zeptomole (<10 −21 mole) analyte detection were accomplished by coating the DFH-4T films with a thin gold layer. Our results offer important guidance for the molecular design of SERS-active organic semiconductors and easily fabricable SERS platforms for ultrasensitive trace analysis. Highly nanostructured purely organic films are shown to enhance the Raman signal of methylene blue molecules by three orders of magnitude, due to the unique molecular geometry, morphology and electronic properties of the films.

In this research, polyvinyl chloride (PVC) with excellent shape‐memory effects is 4D printed via fused deposition modeling (FDM) technology. An experimental procedure for successful 3D printing of lab‐made filament from PVC granules is introduced. Macro‐ and microstructural features of 3D printed PVC are investigated by means of wide‐angle X‐ray scattering (WAXS), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA) techniques. A promising shape‐memory feature of PVC is hypothesized from the presence of small close imperfect thermodynamically stable crystallites as physical crosslinks, which are further reinforced by mesomorphs and possibly molecular entanglement. A detailed analysis of shape fixity and shape recovery performance of 3D printed PVC is carried out considering three programming scenarios of cold (Tg −45 °C), warm (Tg −15 °C), and hot (Tg +15 °C) and two load holding times of 0 s, and 600 s under three‐point bending and compression modes. Extensive insightful discussions are presented, and in conclusion, shape‐memory effects are promising,ranging from 83.24% to 100%. Due to the absence of similar results in the specialized literature, this paper is likely to fill a gap in the state‐of‐the‐art shape‐memory materials library for 4D printing, and provide pertinent results that are instrumental in the 3D printing of shape‐memory PVC‐based structures. This research introduces polyvinyl chloride (PVC) with an excellent shape memory performance for 4D printing via fused deposition modeling (FDM) technology. Shape memory effects are promising and range from 83.24% to 100%. This study can broaden the material choice for 4D printing PVC‐based functional parts for biomedical applications with extreme mechanical durability and actuation controllability.

The fiber-matrix interfacial transition zone (ITZ) governs the mechanical performance and durability of Ultra high performance concrete (UHPC). UHPC has dense microstructure and low porosity, and the thickness of ITZ in UHPC is extremely small. The analysis of microstructure of ITZ in UHPC is very limited. Backscatter electron image (BSE) in combination with traditional methods are applied to the precise quantitative analysis of ITZ in this paper. The results indicated that the porosity decreased rapidly with the increase of the distance from fiber surface. The thickness and porosity of ITZ in SF1-UHPC1, SF2-UHPC2, SF2-UHPC3 were about 38 μm and 12.7%, 18 μm and 12.5%, 12 μm and 9.9%, respectively. With the increase of UHPC strength, the porosity of matrix and ITZ decreased rapidly, and the thickness of ITZ also decreased rapidly.

In the present study, the effect of fabrication parameters on the performance difference of patterned electrode cells is investigated. Ex-situ experiments are conducted on three types of cells: a non-sintered cell with an as-sputtered Ni film, and two sintered cells at 1450 °C and 1700 °C in air, respectively. Current–voltage (I–V) and microstructural analysis revealed that higher sintering temperature enhanced Ni dissolution into yttria-stabilized zirconia (YSZ), which stabilized the Ni–YSZ interface and improved the long-term performance. In contrast, non-sintered and lower-temperature sintering cells exhibited weak adhesion of Ni and rapid degradation in cell performance. These findings highlight that thermally induced Ni dissolution stabilizes the Ni-YSZ interface, emphasizing that thermal processing is a key factor in improving solid oxide electrolysis cell (SOEC) electrode durability.

The Microstructural Hierarchy Descriptor (μSHD) is a systematic and extensible method for quantitative microstructural analysis. In this study, the μSHD method is used to investigate the microstructural evolution of solder joints in various external fields. The results show that the orientation in SAC305 joints is significantly larger on scales from J = 3 to 7 before aging, indicating pronounced network-like structures. However, this phenomenon disappears after isothermal aging, leading to a more uniform distribution of orientation across all scales. In SnAgInBi joints, both the scale and orientation features decrease on scales J < 7 but increase on scale J = 8 after thermal cycling, corresponding to grain coarsening. In Sn37Pb joints, features on orientations L = 1 and 8, which align with the direction of electron flow, show a significant increase after electromigration. Furthermore, features on scales J ≥ 5 increase, while changes on smaller scales are minimal. These findings demonstrate the usefulness of the μSHD method in capturing the nuanced microstructural changes of solder joints subjected to external fields, providing valuable and quantitative microstructural descriptors to establish linkages with the reliability of electronic assemblies.

Additive manufacturing (AM) has gained great importance in the recent development to produce metallic structural elements for civil engineering applications. However, research effort has been focused mainly on powder-based processes, while there is still limited knowledge concerning the structural response of wire-and-arc additive manufactured (WAAM) metallic elements, and very few experimental data concerning their mechanical properties. This paper presents the first results of a wide experimental campaign aimed at assessing the mechanical properties of WAAM plates produced using a commercial ER308LSi stainless steel welding wire. The aim is to evaluate the effect of the orientation in the tensile behavior of planar elements considering specimens extracted along three different directions with respect to the deposition layer: transversal direction (T), longitudinal direction (L), and diagonal direction (D). Compositional, microstructural, and fractographic analyses were carried out to relate the specific microstructural features induced by WAAM to the mechanical properties. The results show that the chemical composition of the plates meets the requirements of UNS-S-30403 for an AISI 304L austenitic stainless steel. The as-built samples were substantially defect-free and characterized by a very fine microstructure of γ and δ phases The fineness of the microstructure and the negligible defect content led to values of tensile strength and elongation to failure in line with the traditionally manufactured stainless steel elements. Anisotropy in the tensile properties between T, L, and D specimens was observed, and the highest elastic and plastic properties were measured in D specimens. This result is related to the crystallographic and mechanical fibering induced by the additive process, that led also, in case of D samples, to the highest density of cell boundaries, obstacles to the dislocation slip, located at 45° with respect to the loading direction, where plastic deformation preferentially occurs.