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As a class of thermosetting resins with exceptional overall performance, cyanate esters have not received sufficient attention for their potential applications in 3D printing. In this paper, polytetrafluoroethylene micropowder is used for the first time as a thixotropic agent to regulate the rheological properties of liquid bisphenol E cyanate monomer for direct ink writing of cyanate ester resins in 3D printing. Due to their appropriate compatibility, the mixed inks exhibit high storage modulus and shear-thinning behavior, enabling the printed structures to maintain their shape well during printing and subsequent curing processes. The printed samples have good mechanical strength and excellent thermal stability. At the same time, the presence of polytetrafluoroethylene endows the composite materials with low dielectric constant and hydrophobicity. The latter property leads to high hygrothermal stability of the composites. The cyanate ester-polytetrafluoroethylene composite developed here offers a reliable method for 3D printing high performance cyanate ester, efficiently enhances the processibility of the cyanate ester based materials. [ABSTRACT FROM AUTHOR]

The regulation of hydrogen content in the continuous casting process is conducive to the reduction of pore defects in the casting billet. In this paper, the influence of negative pressure (NP) and continuous casting speed (CCS) on hydrogen content in copper rod billet prepared by negative pressure continuous casting (NPCC) technique was analyzed, and the mechanism of the coordinated coupling of NP and melt flow on hydrogen removal was revealed. It is clarified that with the CCS of 20 mm min−1 and an increase in the NP value from − 20 to − 80 kPa, the hydrogen content is reduced from 1.0 to 0.3 ppm. The coordinated action of NP and melt flow induced by CCS can minimize the hydrogen content. When the NP value is − 80 kPa and the CCS is 10 mm min−1, the hydrogen content is as low as 0.2 ppm, and the hydrogen removal rate is 85.7%. The larger the NP, the smaller the critical nucleation radius of the hydrogen bubble, and the larger the growth rate of the hydrogen bubble. The coupling of the NP field and flow field can make the melt which is difficult to nucleate and grow of the hydrogen bubble flow to the position which is easy to nucleate and grow. The effect of the vortex fields in the purification chamber on the removal of hydrogen is not affected by the CCS, but the CCS affects the floating of hydrogen at the solidification front, which leads to a small increase in the hydrogen content with the increase of the CCS. Our study provides a theoretical basis for the preparation of high-quality metal billets. [ABSTRACT FROM AUTHOR]

In this paper, a simultaneous thermal analyzer carried out isothermal eutectoid transformation experiments of Fe–0.4Mn, Fe–1.2Mn, and Fe–1.2Mn–0.2Si alloys. The kinetic model of the isothermal phase transformation of FeO was established using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation combined with the experimental data. The kinetic model of the eutectoid transformation of FeO in a non-isothermal process was also established based on Scheil's additivity rule and the mapped-out FeO. The CCT diagram shows that increasing the Mn content and adding Si elements during the continuous cooling process cause the phase zone where the FeO layer undergoes eutectoid transformation to shift to the right. Due to the similarity of crystal structures, the (Fe, Mn)O solid solution formed by FeO and MnO improves the stability of FeO. Mn2+ widens the spacing between oxide ions, and with the increase in Mn content, the Gibbs energy of the formation of (Fe, Mn)O becomes too small to compensate for that of the formation of α-Fe from (Fe, Mn)O. In addition, the temperature point at which the phase transformation of FeO occurs decreases with the increase in Mn content, resulting in the decrease in phase transformation supercooling, so the increase in Mn content will inhibit the eutectoid transformation. The addition of elemental Si resulted in the formation of a cation-deficient FeO with higher O content and lower Fe content, and the time for the Fe2+ concentration to reach supersaturation was prolonged, thus further inhibiting the onset of the eutectoid transformation. [ABSTRACT FROM AUTHOR]

In recent years, SiC single crystal growth technology has been developed toward larger size and thickness to reduce the cost of SiC-based power devices. Resistance heating has gradually become a hot spot for research because the crystals grown by the induction heating display the disadvantages of high stress and defect density. In this paper, the design of resistance heaters for SiC crystal growth was thoroughly investigated via numerical simulation. A simulation of the thermal field generated by different resistive heater arrangements was performed. The stress and dislocation distribution in crystals under different growth conditions were studied. Based on the comprehensive requirements of a small radial temperature gradient and a large growth rate, the arrangement and length of the resistance heater were proposed. This study would serve as a useful guidance for the study of SiC growth by resistive heating. [ABSTRACT FROM AUTHOR]

Tribaloy™ T800, a Co-based alloy, exhibits remarkable tribological properties by virtue of its high-volume fraction of intermetallic Laves phase making it an attractive hard-facing material. Hard-facing by laser deposition results in dilution from the substrate, and thereby, the properties of the clad are altered. This paper reports the influence of processing parameters on the dilution, microstructure, and wear behaviour of Tribaloy™ T800 on AISI 316 stainless steel. A systematic set of 20 clads was deposited by varying laser power and cladding speed, keeping powder flow and spot diameter constant. While dilution decreased at lower laser powers (800 and 1000 W) with increasing cladding speed (5–20 mm s−1), at higher laser powers (1200 and 1400 W), the opposite trend was observed. The Fe intermixing from the substrate along with the cooling rate governs the volume fraction and size of the Laves phases which controls the properties of T800 clads. The clad with the least geometric dilution (5.7%) exhibits the lowest wear rate of 0.54 × 10−5 mm3 N−1 m−1, increasing to 2.88 × 10−5 mm3 N−1 m−1 as the dilution increased to 60%. [ABSTRACT FROM AUTHOR]

In this paper, the compensation characteristics and hysteresis loops of a ferrimagnetic mixed-spin diluted fullerene-like (XY)540 are studied based on Monte Carlo method. We show the ground-state phase diagrams in order to explore the stable configuration states. The temperature dependence of magnetization, magnetic susceptibility, internal energy, specific heat, and entropy are presented. The phase diagram including compensation temperature Tcomp and phase change temperature Tc is obtained. The multi-loop hysteresis phenomena under the influence of diverse physical parameters are observed. Finally, the critical exponents of the fullerene-like (XY)540 are obtained. [ABSTRACT FROM AUTHOR]

For accurate patient identification and treatment, early-stage disease diagnosis is particularly important. However, a lack of patient compliance with the current diagnostic techniques prevents prompt diagnosis, making the creation of noninvasive diagnostic tools essential. Breath analysis, one of the most promising noninvasive diagnostic techniques that has also attracted a lot of research interest recently, finds gas analytes like exhaled volatile organic compounds (VOCs) and inorganic gases that are thought to be significant biomarkers for a variety of disease types. The common technique for the detection of biomarkers in breath involves spectrometric-based measurements. Despite their precision and accuracy to detect a low concentration of exhaled breath, these techniques have some disadvantages such as lack of portability, being expensive, high power demand, and requiring trained staff to operate them. Consequently, recent interest in nanotechnology has accelerated the development of new chemosensors, sensing techniques, and enhanced the performance and sensitivity of existing chemosensors in the rapidly evolving field of biosensing. Chemosensors made with nanotechnology can identify diseases and monitor treatment outcomes. This review paper aims to present a current overview of the major chemosensor categories investigated for applications in disease diagnosis via the detection of exhaled gas analytes and to emphasize the significance of nanomaterials. Various nanomaterial-based chemosensors, prepared with several metal and metal oxide nanoparticles for detections of different types of volatile organic compound biomarkers. [ABSTRACT FROM AUTHOR]

In this paper, high-density (60−x)Fe−Cr−Co−xCu (x: 0–6 wt.%) permanent magnet alloys were fabricated by laser powder bed fusion (LPBF) in-situ alloying technique, and the effects of Cu content on the microstructure, magnetic, and mechanical properties of the alloy were systematically investigated. The addition of 2 wt.% Cu enhanced the coercivity H c and the energy product (B H) max of the alloy in the isotropic state by 19.4 and 27.9%, respectively, compared to the alloy without Cu. The impacts of Cu content on the magnetic properties were investigated by combining experimental results and first-principles calculations. Furthermore, the addition of Cu improved the yield strength of the alloy, and the strengthening mechanism was analyzed in detail. The yield strength of the alloy with 2 wt.% Cu reached 908 MPa, representing a notable 7% increase relative to the Cu-free alloy. [ABSTRACT FROM AUTHOR]

One of the effective ways to achieve drilling of Carbon fiber reinforced polymer (CFRP) materials is to use short pulse lasers. However, the existing cutting thermal damage, such as the heat-affected zone (HAZ), can weaken the CFRP mechanical properties. In this paper, a heterogeneous mesoscopic model of transient distribution of short pulse laser ablation heat flow is built to fully explore the formation and extension mechanism of thermal damage. The significant difference in laser interaction thermal effects between fibers and resin leads to the formation of HAZ with exposed fibers. The interface effect exists in the ablation process, which aggravates the matrix damage. The ablation of carbon fibers occurs within the duration of a single laser pulse, and the degree of ablation depends on the pulse energy. Under the coupling of the thermal conduction effect along the fiber axis and the thermal accumulation effect between pulses, the matrix damage extends significantly during the cooling stage. Large pulse repetition frequency increases heat accumulation between pulses and increases matrix damage. There is a new erosion mechanism in that the thermal accumulation behavior leads to the falling off of fragmented carbon fiber filaments. The accuracy of the model was verified through different pulse ablation tests, and the average error of ablation morphology is 11.28%. [ABSTRACT FROM AUTHOR]

As a new functional material, metal halide perovskites provide new possibilities for preparing gain media for nanosemiconductor lasers. This paper reviews the fabrication results of nanosemiconductor lasers based on metal halide perovskite materials. Firstly, three standard metal halide perovskite-based nanosemiconductor lasers are described: thin-film, nanowire, and quantum dot lasers. Under the corresponding gain structure of each laser, the appropriate gain dielectric material is discussed, and its application in the fabrication of nanosemiconductor lasers is discussed. On this basis, the effects of these gain structures and metal halide perovskite materials on the performance of nanosemiconductor lasers and related application progress are analyzed. Finally, the challenges and opportunities of nanosemiconductor lasers based on metal halide perovskite materials are summarized and the future development trend was discussed. [ABSTRACT FROM AUTHOR]

With the continuous downsizing of solder joints, the influence of the grain characteristics of the under bump metallization (UBMs) on the interfacial reaction is exposed. In this paper, the effect of grain characteristics of Cu UBM on the growth of interfacial intermetallic compounds and the formation of Kirkendall voids in Cu/Sn/Cu micro solder joints during isothermal aging at 150 °C was investigated. Electroplated polycrystalline Cu (EP-Cu), (111) single crystal Cu ((111) Cu), and (111) nano-twinned Cu ((111) nt-Cu) were selected as UBMs. After reflow soldering, the Cu6Sn5 grains formed on (111) nt-Cu were near to the orientation (2 1 - 1 - 3) , while those were randomly formed on both EP-Cu and (111) Cu. During isothermal aging, the Cu6Sn5 grains exhibited the highest growth rate on (111) nt-Cu UBM, and the slowest growth rate on (111) Cu UBM, due to the differing number of diffusion routes among the three Cu UBMs with distinct grain characteristics. Furthermore, no Kirkendall voids were detected on the (111) Cu UBM, however, a significant number of Kirkendall voids were identified on the (111) nt-Cu UBM, which can be attributed to the diffusion path and impurities present in the three Cu UBMs. The results will offer theoretical and practical recommendations for the selection of Cu UBMs for micro solder joints in 3D packaging interconnection technology. [ABSTRACT FROM AUTHOR]

To investigate the dynamic recrystallization (DRX) behavior of forged 42CrMoA steel during hot deformation, the hot deformation experiments of forged 42CrMoA steel under different deformation conditions (strain rate, temperature, and strain) were carried out in this paper. The hot deformation activation energy of forged 42CrMoA steel was determined to be 413627.2 J · mol - 1 . The constitutive model and DRX kinetic model of the steel were established. Analyzing the reconstructed parent phase grains reveals that when the strain is constant, as the deformation temperature increases and the strain rate decreases, the average size and DRX volume fraction of the parent phase grains gradually increase, and the peak stress gradually decreases. When the deformation temperature and strain rate are constant, as the strain increases, the average size of the parent phase grains gradually decreases, and the volume fraction of DRX gradually increases. Based on the cellular automaton theory model and considering the influence of grain deformation on the DRX process, a cellular automaton dynamic recrystallization (T-DRX-CA) model for forged 42CrMoA steel based on topological deformation technology was established, and the microstructure evolution under different deformation conditions was simulated. The microstructure evolution under different deformation conditions was simulated, which was compared with experimental results. The results showed that the average errors between the simulated and experimental values of the average grain size of the parent phase, the volume fraction of DRX, and peak stress were all less than 8%, and the simulated results were in good agreement with the experimental values, which indicates that the established model can accurately predict the DRX behavior of the forged 42CrMoA steel in the process of hot deformation. The hot deformation behavior of forged 42CrMoA steel under different deformation conditions was investigated by a cellular automaton dynamic recrystallization (T-DRX-CA) model based on topological deformation technique. The results showed that the average errors between the simulated and experimental values of the average grain size of the parent phase, the volume fraction of DRX, and peak stress were all less than 8%, and the simulated results were in good agreement with the experimental values, which indicates that the established model can accurately predict the DRX behavior of the forged 42CrMoA steel in the process of hot deformation. [ABSTRACT FROM AUTHOR]

The escalating use of fiber-reinforced composites (FRCs) in aerospace, defense, automotive, and renewable energy industries underscores the need for a comprehensive understanding of their impact resistance and damage tolerance. This review meticulously examines low-velocity impact (LVI) on FRCs, covering impact mechanics, velocity classification, energy absorption, fiber architecture, and hybridization. Emphasizing the critical importance of damage assessment, the study analyzes intricate failure mechanisms and damages induced by LVI, addressing their potential impact on composite structural attributes. The paper critically reviews parameters influencing impact resistance and damage mechanics, evaluating performance through instrumented drop-weight impact testing. Additionally, the review explores nondestructive testing methods crucial for ensuring the reliability of composite structures. The aerospace sector and other applications requiring enhanced dynamic loading characteristics stand to benefit from a deeper understanding of composite behavior under transient impact loading. Specifically focusing on woven textile-reinforced composites, which offer specific material properties and a cost-effective manufacturing route. However, their susceptibility to out-of-plane impact loading leads to various failures, including delamination and spalling, limiting their applicability in advanced scenarios where structural integrity is paramount. It discusses advanced technology like 3D weaving as reliable methods to enhance impact resistance, damage tolerance, and delamination resistance. Notably, 3D woven composites demonstrate superior through-thickness fracture toughness, eliminating delamination as a failure mode. The findings offer valuable insights for designing structures with enhanced compression after impact and through-thickness tension characteristics. Overall, this review consolidates key advancements, challenges, and future prospects in the realm of woven composite materials and their behavior under impact loading, providing a valuable resource for academics and industry professionals alike. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) metal halide perovskites feature several specific advantages over others 2D materials, such as facile wet chemical synthesis and layers exfoliation, high composition combination especially the choice of organic cations as well as 2D phase, excellent confinement for exciton. In this paper, we present a fundamental study of diaminonaphthalene lead iodide (DANPI) perovskite, a Dion–Jacobson 2D perovskite based on divalent cation organic spacer 1,5-diaminonaphthalene. We report its material synthesis, optical and structural characterization as well as DFT calculations. Hydro-iodic acid-based wet chemistry was used to prepare DANPI crystals and, by cast-capping, thin films as well. Both DANPI materials show a dominant emission peak at about 519 nm with a full width at half-maximum as small as 14 nm. This peak coincides with the absorption edge of the material at 510 nm (2.43 eV) which suggests an exciton-related recombination process. According to single-crystal X-ray diffraction measurements the crystal structure could be either monoclinic P21/c or tetragonal P4212. DFT calculations including spin–orbit coupling show that the DANPI band gap is direct, with a valence band of s-symmetry and a conduction band of p-symmetry. A dominant emission peak at about 519 nm with a full width at half-maximum as small as 14 nm. The crystal structure could be either monoclinic P21/c or tetragonal P4212. The DANPI band gap is direct, at 2.43 eV, with a valence band of s-symmetry and a conduction band of p-symmetry. Suggested Dexter electron exchange process for Wannier excitons to organic Frenkel excitons. [ABSTRACT FROM AUTHOR]

The alloy composition and sensitization behavior are crucial factors that cannot be overlooked in Al–Mg alloys. The effect of Zn addition on mechanical properties and sensitization behavior of 5083 alloy was investigated by tensile tests, weight loss experiments, and first-principles calculation in this paper. The results show that Zn can significantly improve the strength and sensitization behavior of the alloy. The tensile strength of the cold-rolled alloy increased from 459 to 498 MPa with the addition of 1.5%Zn. Furthermore, by incorporating 2.0% Zn, the mass loss of the cold-rolled alloy after sensitization at 170℃/1 h decreased from 49.3 mg·cm−2 to 19.5 mg·cm−2. First-principles calculations indicate that Mg clusters can only exist stably near grain boundaries, while Mg–Zn clusters can exist stably both within and at grain boundaries. This reduces the number of corrosive media at grain boundaries and weakens their continuity. Moreover, the energy barrier that T-phase precipitation needs to overcome during precipitation is lower than β-phase, which transforms the stabilization schedule of the alloy from 240℃/12 h without Zn to that 210℃/4 h with 2.0% Zn-containing. The synergistic effects of Zn content and sensitization on the properties of the alloy were revealed, which sheds some light for the design of the composition and processing method according to application scenarios. [ABSTRACT FROM AUTHOR]

The effect of the grain boundary (GB) misorientation on plastic deformation of Inconel 718 (IN718) alloy was investigated in this paper, using in-situ tensile experiment at 650 °C in combination with crystal plasticity finite element method (CPFEM). The results indicate that dislocations tend to accumulate at GBs to form stress concentration, but the degree of stress concentration does not necessarily increase with the increase of the GB misorientation. It is attributed to the slip transfer at the GBs, determined by the angle between the slip systems of the two adjacent grains. There is a significant uncertainty in the slip transfer for GB misorientation larger than 10°. However, the m α β ′ SF α + SF β criterion, which is a function of the Luster and Morris m α β ′ combining the Schmid factors of the two slip systems with the GB misorientation, has some statistical separation significance. Slip transfer tends to appear at GB misorientation less than 30° and m α β ′ SF α + SF β > 0.78 . This study clarifies the mechanism of the influence of GB misorientation on IN718 microplastic deformation and provides a new strategy to study the deformation behavior of superalloys. [ABSTRACT FROM AUTHOR]

This paper presents the nickel–cobalt nanoprickly particles (PNi2Co3) composited with graphene nanosheets (GNs) and carbon nanotubes (CNT), prepared via the one-pot hydrothermal method (PNi2Co3/GNs/CNT), as an efficacious nonprecious metal bifunctional electrocatalyst for both oxygen evolution and reduction reactions (OER/ORR). The study employs a comprehensive methodology, incorporating cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) analysis to characterize and assess the materials and electrochemical properties investigated in the article. The primary objective was to successfully prepare a bifunctional electrocatalyst, and the PNi2Co3/GNs/CNT material achieved this goal. It exhibited superior OER activity, durability, and resistance to crossover effects, by an overpotential (η) of 480 mV and a Tafel slope of 61 mV dec−1, significantly higher than those obtained for RuO2 nanoparticles (η = 970 mV, Tafel slope = 85 mV dec−1). A similar trend was observed for ORR, where the PNi2Co3/GNs/CNT displayed high activity with an n = 3.93, close to the activity of a Pt/C (20 wt%), commercial catalyst with n = 4. Careful analysis of the EIS results via suitable models, in conjunction with Tafel data, revealed that the enhanced activity originates mainly from two factors: (a) the large surface area of the Ni–Co nanoprickly alloy and graphene sheets, where the CNTs (as a spacer) helped graphene nanosheets to avoid restacking and decreasing the surface area, and (b) the synergistic effect between Ni–Co nanoprickly and carbon components (GNs and CNT) of the composite. [ABSTRACT FROM AUTHOR]

Recently, papers with superhydrophobic surfaces and unique antibacterial and self-cleaning capabilities have attracted great attention due to its potential applications in cold chain logistics packaging. Therefore, a facile and versatile route to fabricate superhydrophobic and anti-bacterial adhesion dual-functional paper was reported. The approach was based on pufferfish-like structured ZIF-8 incorporated cellulose fibers. Specifically, cellulose fibers without any chemical pretreatment were used as templates for the in situ aqueous construction of pufferfish-like structured ZIF-8 with zinc nitrate as zinc source and dimethylimidazole as organic ligand. After paper-making and hydrophobicity treatment, the obtained paper possessed excellent superhydrophobic and anti-bacterial adhesion properties. These surfaces retained their water resistance after 30 finger-wipe cycles and 10 sandpaper abrasions. Moreover, the hydrophobic surface prepared also showed excellent anti-adhesion performance toward bacteria. This strategy route proposed here can significantly reduce or eliminate potential risks associated with various contamination. [ABSTRACT FROM AUTHOR]

The Journal of Materials Science is known for publishing papers on polymer materials. The journal has several editors who specialize in polymers, including Chris Cornelius, Steve Eichhorn, Jamie C. Grunlan, Dale Huber, Maude Jimenez, Greg Rutledge, Jean-François Gohy, and Mohammad Naraghi. These editors handle papers on a wide range of topics related to polymers, including composites, materials for the life sciences, coatings, electronic materials, chemical routes to materials, and ceramics. Each editor has their own area of expertise and has made significant contributions to the field. The journal is a valuable resource for researchers interested in polymeric materials and related topics. [Extracted from the article]

In this paper, EFKA FA 4663 (EFKA) dispersant was used for the first time in the alumina slurries tert-butyl alcohol-based freeze-casting and compared to the commonly used anionic dispersant citric acid (CA). The comparison of both dispersants was analyzed at the beginning of the process at different ultra-low freezing temperatures (− 170 to − 130 °C). The monoliths obtained with EFKA presented promising properties due to its stabilization of alumina particles by both electrostatic interactions and steric impediment, a considerable improvement when compared to the CA that promotes the stabilization of alumina particles only by electrostatic interaction. The use of different dispersants, as well as the control of freezing temperature, significantly influenced the microstructural properties of the monoliths. The monoliths exhibited prismatic pore geometry with high connectivity, forming a complex pore channel with total porosity up to 64.7%, and open porosity up to 48.5%. Results confirmed that the modification of the type of dispersant led to a difference in the grain size (up to 23.1%) and pore size (up to 30.5%) obtained in the materials. The monoliths produced with EFKA dispersant presented a considerable compressive strength resistance up to 11.7 MPa due to its dispersion mechanism that provided the thickening of the walls, confirming that the type of dispersion has a strong influence on the final properties of the materials. Therefore, the type of dispersant proved to be another parameter that allows the refinement of alumina monoliths properties, highlighting the use of EFKA as a promising alternative in the system studied. [ABSTRACT FROM AUTHOR]

In this study, four ZrNxOy coatings were deposited on the surface of Ti–45Nb alloy by multi-arc ion plating technology at different N/O ratios. The effects of oxygen content on the mechanical properties, wear resistance, electrochemical corrosion and tribocorrosion properties of the coatings were investigated separately. As the increasing of O2 ratio, the hardness value decreases from 30.2 to 9.7 GPa; the Young's modulus values decrease from 322.1 to 172.2 GPa. The H/E and H3/E2 values showed a decreasing trend with the increasing O2, which indicates a gradual decrease in the load-bearing capacity of the coatings. The critical load of these coatings in scratch test ranges from 12 N, 7.2 N, 5 N to 3N. In the friction test, both the TiNb alloy and coating exhibited predominantly abrasive and adhesive wear. The relatively low wear rate of the ZrN coating demonstrated its excellent wear resistance; however, the wear-resisting property of the ZrNxOy coating gradually decreases as the oxygen content increases, and ZrO2 coating showed the poorest wear resistance. On the contrary, the higher the oxygen content, the better the electrochemical corrosion resistance, and ZrO2 coating showed the excellent corrosion resistance. The results of tribocorrosion test show that the ZrNxOy coating has better wear resistance in simulated body fluid solution compared to Ti–Nb alloys. The experimental results and design concepts of the paper can provide a better understanding of the preparation of medical titanium alloy surface functional coatings with good comprehensive performance. [ABSTRACT FROM AUTHOR]

This paper focuses on the effect of laser shock peening on the rotational bending fatigue life of S51740 stainless steel round bar specimens. The improvement of material properties by laser shock peening is investigated by combining simulation calculations and experiments. The main results are as follows: Finite element simulations yielded three sets of laser process parameters for the study (LPS-1, LSP-2, LSP-3). The fatigue test results show that laser impact strengthening can effectively improve the fatigue life of the material, and compared with the unenhanced specimens, 350% increase in fatigue life of LSP-2 specimens. EBSD analysis showed that the LSP-2 specimen performed the best. It was verified that the material properties of S51740 stainless steel were greatly improved when the laser process parameter was LSP-2. [ABSTRACT FROM AUTHOR]

The fashion and textile manufacturing sectors are increasingly focusing on innovative raw materials that are renewable and biodegradable. Such materials not only mitigate environmental impacts but also prevent resource depletion. Bacterial cellulose (BC) has emerged as a prime candidate, derivable from a variety of natural ingredients such as tea and coffee in addition to a sugar source in presence of the bacterial microorganisms. Numerous studies have established the potential of BC in future fashion, and some brands have already started to utilise BC as a sustainable raw material. The applications of BC ranges from basic clothing and accessories to wearable electronics. This paper discusses the scope of BC in fashion and textiles, positioning it as a sustainable alternative to conventional materials. We present a comprehensive scoping review, covering the unique properties of BC, the factors influencing its production, and its applications in textile, clothing, and footwear over the past decade. The advantages of BC in fashion are manifold: zero-waste manufacturing, reliance on renewable sources, diminished environmental pollution, and biodegradability. Furthermore, the use of BC aligns with United Nations Sustainable Development Goals 6, 7, 12, 13 and 15. However, there exist challenges pertaining to production costs, scalability, and quality, in addition to the imperative of harnessing food waste streams instead of contending for human food resources. Addressing these challenges is vital to cement BC's position as a pivotal sustainable material in future fashion. [ABSTRACT FROM AUTHOR]

Many important properties of bacterial cellulose (BC), such as moisture absorption capacity, elasticity and tensile strength, largely depend on its structure. This paper presents a study on the effect of the drying method on BC films produced by Medusomyces gisevii using two different procedures: room temperature drying (RT, (24 ± 2 °C, humidity 65 ± 1%, dried until a constant weight was reached) and freeze-drying (FD, treated at − 75 °C for 48 h). BC was synthesized using one of two different carbon sources—either glucose or sucrose. Structural differences in the obtained BC films were evaluated using atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray diffraction. Macroscopically, the RT samples appeared semi-transparent and smooth, whereas the FD group exhibited an opaque white color and sponge-like structure. SEM examination showed denser packing of fibrils in FD samples while RT-samples displayed smaller average fiber diameter, lower surface roughness and less porosity. AFM confirmed the SEM observations and showed that the FD material exhibited a more branched structure and a higher surface roughness. The samples cultivated in a glucose-containing nutrient medium, generally displayed a straight and ordered shape of fibrils compared to the sucrose-derived BC, characterized by a rougher and wavier structure. The BC films dried under different conditions showed distinctly different crystallinity degrees, whereas the carbon source in the culture medium was found to have a relatively small effect on the BC crystallinity. [ABSTRACT FROM AUTHOR]

In low- to middle-income communities, the lack of affordability of conventional sanitary products during menstrual cycles can cause psychological and health issues, ultimately affecting their quality of life. It is crucial to develop alternative products that are affordable and accessible to all while also promoting menstrual health and hygiene. Super absorbent polymers (SAPs) are a vital component in current disposable sanitary pads and nappies. However, these SAPs are often non-biodegradable and non-biocompatible. Therefore, the use of eco-friendly materials for the production of SAPs is gaining popularity in the hygiene industry, as it offers a means to reduce the carbon footprint and environmental impact associated with traditional SAPs made from non-renewable petroleum-based materials. SAPs made from polysaccharides often have naturally occurring antibacterial properties, making them appealing for commercial applications in sanitary products such as sanitary pads. In addition, the move toward reusable sanitary pads with antibacterial properties can significantly reduce waste generated by single-use products and prevent the growth of bacteria, improving the safety and hygiene of the product. Furthermore, computational modeling and artificial intelligence are now important tools in SAP synthesis, providing advantages such as predicting polymer properties, rationalizing synthesis pathways, and improving quality control. These tools can reduce synthesis costs by eliminating the need for trial-and-error approaches in polymer synthesis, ultimately promoting more affordable products for end users. Overall, these advancements in polymer synthesis and material design can help to create a more sustainable industry and promote menstrual hygiene and product accessibility to those who need it most. [ABSTRACT FROM AUTHOR]

Presently, special metallic materials (titanium and a number of its alloys, stainless steels, magnesium alloys, etc.) are extensively used for the manufacturing of many medical tools and devices and choosing the appropriate material is of vital importance as it determines the success and safety of the medical devices for their application. Recent years witnessed active research and development to improve the mechanical and functional properties of these biomaterials using their nanostructuring by means of severe plastic deformation (SPD) techniques. The specific nanostructural features induced by SPD processing in metallic biomaterials significantly contribute to their performance, which has been evidenced in a series of investigative activities conducted lately to improve existing metallic biomaterials and explore potential for their production capability. This paper presents a review of these works and considers the scientific principles of achieving a higher level of properties in the metallic biomaterials as well as related challenges and uncertainties, which forms the basis for the production of a new generation of medical implants with improved design and increased biofunctionality. [ABSTRACT FROM AUTHOR]

In this paper, the effect of deep cryogenic treatment (DCT) on the microstructure and properties of automotive 6063 aluminum alloy at different times was investigated with automotive 6063 aluminum alloy as the research object. The results show that under the conditions of deep cryogenic treatment, the lattice distortion occurs in the alloy matrix microstructure, and the resulting internal stress promotes the large proliferation of dislocations within the alloy and the increase of dislocation density; meanwhile, after the deep cryogenic treatment, the deformed grains are transformed into recrystallized and sub-crystals structural grains, the grains are refined, and the size of the grains is refined from the original 25.2 μm to 20.3 μm, with fine equiaxed crystals. Among them, the mechanical properties of the DCT36h specimen were the best, and its hardness, tensile strength, yield strength and elongation reached 142.44 HV, 328.32 MPa, 177.42 MPa, and 29.29%, which were 34.17%, 5.62%, 11.10%, and 32.77% higher than the original sample, respectively. We believe that the main mechanism for the increase in toughness is multiple reinforcement such as dislocation strengthening, grain refinement strengthening, precipitated phase strengthening and texture strengthening. [ABSTRACT FROM AUTHOR]

Solar-driven interfacial evaporation is a sustainable and green desalination method with great prospects for development in today's severe water shortage problem. In this paper, a novel composite aerogel was prepared by hydrothermal method with sodium alginate (SA) and Cu2+ in the preparation process using reduced graphene oxide as photothermal material and cellulose nanofibers as substrate. The good hydrophilicity of nanocellulose makes the composite aerogel have strong capillary action and continuous water transport. The gel formed by ion exchange between SA and Cu2+ greatly improves dry and wet mechanical strength of the composite aerogel and ensures the stability of the evaporator for multiple recycling. Copper is doped by reduction of copper ion complexes and reduced graphene oxide have a synergistic effect to increase the photothermal response rate of the composite aerogel of 1.446 kg m−2 h−1 with evaporation efficiency of 84.87% under one standard solar irradiation. In addition, the purification of heavy metal ions, dye wastewater as well as acid and alkali solutions also has excellent results. It is expected that this study will provide some new ideas for the fields of seawater desalination and wastewater treatment. [ABSTRACT FROM AUTHOR]

Simulation models are used to emulate real-world phenomena, and errors are inevitable in the numerical computation process. Owing to that, simulation models need to be verified and validated to ensure the models and their implementations are correct. In this paper, V&V has been done for the micro3d discrete dislocation dynamics (DDD) model by comparing simulation results with corresponding theory, including any analytical solutions, other numerical solutions and experimental data. DDD simulations are a powerful simulation methodology that can help researchers better understand the plastic behavior of crystalline materials. In this study, parametric analyses for DDD simulations parameters have been performed. In addition, simulation results are verified and validated. [ABSTRACT FROM AUTHOR]

This three-part paper lends new insight into the interpretation of internal state variable (ISV) theory and fundamentals of the behavior of thermally activated dislocation ensembles. We formally define important physical concepts undergirding ISV theory such as configurational subsystems (e.g., individual grains or phases), constrained local equilibrium, and thermally activated dislocation reactions in the context of crystal plasticity and then implement these concepts within a nonequilibrium statistical thermodynamics framework. The primal importance of the Gibbs free energy barrier to dislocation reactions within each subsystem is emphasized since the enthalpy barriers are affected by local constraint and resulting long-range and short-range athermal internal stresses acting within subsystems. Kinetic and kinematic aspects of individual dislocation reactions are defined. The role of athermal internal stresses in stabilizing the positions of dislocations between barriers is acknowledged by the formal identification of the anelastic deformation, along with its role in contributing to thermal dissipation. Thermal and configurational intrinsic entropy change that contribute to the change of Gibbs free energy as a driving force for reactions are formally introduced in the same way as in first principles methods and are based on probability of pending dislocation reactions at each step. We distinguish equilibrium thermodynamics up to the saddle point of reactions, for which change of both configurational and thermal entropy applies, from post-saddle point extended glide of dislocations, which couples with the thermal bath via dispersive phonon dynamics. We write subsystem and ensemble relations for intrinsic entropy production. The concept of "degree-of-correlation" of the enthalpy barriers of thermally activated dislocation processes is introduced at both the subsystem level and across the overall ensemble of subsystems, based on the ratio of the weighted average enthalpy barrier to the maximum (rate-limiting) enthalpy barrier. It is argued that nonequilibrium trajectories progressively move toward correlated behavior of the ensemble by virtue of internal stress redistribution among interacting subsystems that are favorable and unfavorable to reactions. The degree-of-correlation is a many-body concept involving populations of dislocations within and among various configurational subsystems. [ABSTRACT FROM AUTHOR]

Ni-based wrought superalloys are a type of superalloy produced through casting-forging processes, and usually their high-temperature performance is strongly influenced by microstructure and deformation mechanism. The typical microstructure of Ni-based wrought superalloys after heat treatments comprises equiaxed grains, numerous annealed twins, carbides within the grain interior and/or at grain boundaries, and spherical γ′ precipitates (typically comprises around 20% of their volume). The common deformation mechanisms in Ni-based wrought superalloys mainly include anti-phase boundary formed by paired dislocations shearing γ′ phase, stacking fault formed by single dislocation shearing γ′ phase, dislocation bypassing γ′ phase (precipitation-strengthened) and dislocation entanglement, dislocation networks (solid solution strengthened). In this paper, the microstructure and deformation mechanism of tensile and creep in Ni-based wrought superalloys for Advanced ultra-supercritical (A-USC) power plants are reviewed, for the two prominent areas of current research, Ni–Fe-based wrought superalloys exhibit superior processability and cost-effectiveness compared to Ni–Co-based wrought superalloys, thereby offering a more advantageous solution. [ABSTRACT FROM AUTHOR]

This paper explores the hydrothermal treatment of α-Al2O3 powders to improve the binding in ceramic parts produced via a chemical bonding of ceramic powders combining a phosphate binder and infrared (IR) curing. Alumina powders are pre-treated in hydrothermal conditions with both water and phosphoric acid solution before slurry preparation and infrared irradiation. The effects of hydrothermal treatments on the powder's chemical reactions and the composite's final microstructure are assessed upon IR irradiation. While the water treatment does not induce any chemical changes, the presence of phosphoric acid leads to the appearance of phosphate phases Al(PO3)3 and AlPO4. Hydrothermal treatments in water and in phosphoric acid solution are found to drive faster and more intense phosphate condensation reactions at lower temperatures, with a stronger effect in the presence of H3PO4 (condensation temperature of 150 °C for the H3PO4-hydrothermal treated powder compared to 165 °C for the untreated powder). This improved reactivity of hydrothermal treatment α-Al2O3 powders, especially in the presence of H3PO4, leads to a general decrease of porosity for 3D printed parts compared to untreated alumina (for both top surfaces and cross-sections). While further optimization is needed to reduce the final porosity, it is possible to rapidly print 3D parts using this method, demonstrating a possible pathway to a single-step additive manufacturing (AM) process for ceramics. [ABSTRACT FROM AUTHOR]

Alkali-activated materials (AAM) are crafted to address escalating environmental concerns by utilizing low-carbon industrial waste, thus satisfying the need for innovative alternatives to conventional Portland cement (PC). However, the sustainability profile and cost-effectiveness of AAM depends significantly on the choice of commercial activator, with the high carbon footprint and cost of the activator serving as significant obstacles that limit the utilization of the AAM large-scale construction projects. Some locally available agricultural or industrial alkaline wastes have been researched as activators to activate other materials for AAM preparation, fundamentally eliminating AAM's activator-related drawbacks. All-waste alkali-activated materials (AWAAM) not only solve the issue of alkaline waste disposal but also exhibit satisfactory mechanical properties, along with environmental and economic advantages. This paper provides a comprehensive overview of the current phase of cementitious materials that do not require additional commercial alkali sources and are prepared entirely from waste materials, which is AWAAM. It describes the sources of alkaline wastes, elucidates the principles of synergistic interactions between these materials, explores the enhancement of AWAAM, and evaluates the cost, environmental impacts, and ionic leaching behaviors of AWAAM. Nevertheless, numerous studies have not examined the durability, leaching of hazardous materials, and workability of AWAAM. [ABSTRACT FROM AUTHOR]

The material choice for electrical contacts fundamentally governs the breaking performance, safety, and reliability of electrical switches. In recent years, amid a rapid escalation in infrastructure development, an upsurge in living standards, and advancements in scientific and technological realms, there has been a burgeoning demand for increased load capacity within power distribution systems, thereby imposing novel demands on electrical contact materials. The advent of two-dimensional graphene, with its exceptional electrical conductivity, thermal conductivity, and mechanical attributes, has piqued the interest of researchers in the electrical contact field. This has spurred further research and development into innovative graphene-enhanced electrical contact materials. This paper presents a comprehensive review of the progression made in graphene-enhanced silver-based electrical contact materials over the recent years. It particularly delves into the application of graphene in silver-based contact substances, encompassing the most recent developments in graphene-enhanced contacts, the underlying principles and processes governing arc generation and erosion, the arc-resistant mechanisms inherent to graphene-enhanced contact materials, and provides a forward-looking perspective on the potential future of graphene-based contact materials. [ABSTRACT FROM AUTHOR]

Highly integrated and high-power devices place higher demands on the heat dissipation capability of heat sink components, and graphene meets the heat dissipation requirements due to its extremely high thermal conductivity of 5300 Wm−1 K−1 and good mechanical properties. Graphene by redox is one of the most promising methods for large-scale preparation of graphene; however, the quality of graphene prepared by different reduction processes varies. Herein, this paper presents a fast and efficient reduction process. Benzene was added as a reduction aid to increase the temperature from room to 2000 °C in 30 s and complete the reduction process. By this method, we obtained graphene with low defects and high thermal conductivity. The reduction process restored the lattice destroyed by the oxidation process, and the repaired material showed a higher crystallinity with a measured ID/IG of 0.18 (Ph-rGO-0, 0.58) and in-plane thermal conductivity of 510 ± 10 Wm−1 K−1. The in-plane thermal conductivity was increased by 262 Wm−1 K−1 compared with the film without benzene addition (Ph-rGO-0), which showed better homogeneous temperature performance and heat dissipation performance in practical applications. These results show the great potential for the application of graphene films prepared by this method in the field of heat dissipation materials. [ABSTRACT FROM AUTHOR]

Y2O3 materials have been widely applicated in high temperature industry owing to its high temperature stability. However, the poor sintering behavior and thermal shock resistance limited its application. The existing studies were focused on its sintering properties, yet the increase in densification of Y2O3 materials could weaken its thermal shock resistance. Y2O3 materials with smaller closed pores were fabricated by the decomposition of Al(OH)3 and the effect of Al(OH)3 on the microstructure, mechanical properties and thermal properties of Y2O3 materials were investigated in this paper. We concluded that the migration of grain boundaries was accelerated due to the ionic radii difference and the diffusion coefficient between Y3+ and Al3+, and the diffusion coefficient of Y3+ was relatively weak while the diffusion of Al3+ was mainly dominated. The Al2O3 produced by decomposition of Al(OH)3 was active, which promoted the sintering of Y2O3 materials. Meanwhile, the porosity and pore structure of Y2O3 materials were affected by the decomposition of Al(OH)3, and the appropriate pores improved the thermal shock resistance by absorbing thermal stresses. Furthermore, it indicated that adding Al(OH)3 into Y2O3 materials had a powerful influence in balancing its sintering properties and thermal shock resistance. The sample with 3 wt% Al(OH)3 exhibited the better performance in this study, with the relative density of 93.2% and the thermal shock stability factor parameter Rst of 1.74 W m1/2. [ABSTRACT FROM AUTHOR]

In the recent years, molybdenum disulfide (MoS2) has been widely used in various optical applications. MoS2 has decent optical band gap and can be used as photocatalyst for hydrogen production applications. In this paper, we reported the synthesis of flower-like nickel (Ni)-doped MoS2. The as-prepared Ni@MoS2 has optical band gap of 1.71 eV which was lower than that of the pristine MoS2 (1.90 eV). Thus, Ni@MoS2 was further used as photocatalyst for hydrogen evolution. The effect of different dose (5, 10, 15, 20 and 25 mg) of the photocatalyst (Ni@MoS2) was also examined. The photocatalytic investigations exhibited the generation of good hydrogen production amount (2021.5 µmol g−1) with reasonable hydrogen generation rate of 404.3 µmol g−1 h−1 using 25 mg Ni@MoS2. These findings suggested that doping may significantly improve the photocatalytic hydrogen production. The proposed Ni@MoS2 also presented good stability and reusability for hydrogen production. [ABSTRACT FROM AUTHOR]

The demolding process of electroforming technology in fabricating microstructured optical-functional thin films produces the problem of excessive bonding between the metal substrate and the metal replica, which triggers the deformation of the microstructure and the reduction of precision, and the deposition of Cr–O–C discrete nuclei at the interface can play a good role in assisting the demolding effect. In this paper, the tensile deformation of polycrystalline Cu/Ni and Cu/Cr–O–C/Ni composites is investigated using molecular dynamics methods. The results show that the Cu/Ni model produces a large number of HCP structures during stretching, with holes at the interface and a large number of Cu atoms transferring to the Ni layer. The addition of the Cr–O–C layer reduces the yield strength of the Cu/Cr–O–C/Ni model by 26.41%, and at the same time, the dislocation proliferation at the interface is reduced, and the fracture is at the centralized interface, and the fracture time is reduced by 90.8%. The higher number of Cr–O–C atoms at the interface decreases the transfer of Cu atoms to the Ni layer. The results provide a possible explanation for the Cr–O–C layer-assisted precision electrodeposition debonding. [ABSTRACT FROM AUTHOR]

This paper outlines a new approach to designing tunable electromagnetic (EM) graphene-based meta-surfaces using convolutional neural networks (CNNs). EM meta-surfaces have previously been used to manipulate EM waves by adjusting the local phase of subwavelength elements within the wavelength scale, resulting in a variety of intriguing devices. However, the majority of these devices have only been capable of performing a single function, making it difficult to achieve multiple functionalities in a single design. Graphene, as an active material, offers unique properties, such as tunability, making it an excellent candidate for achieving tunable meta-surfaces. The proposed procedure involves using two CNNs to design the passive structure of the graphene meta-surfaces and predict the chemical potentials required for tunable responses. The CNNs are trained using transfer learning, which significantly reduced the time required to collect the training dataset. The proposed inverse design methodology demonstrates excellent performance in designing reconfigurable EM meta-surfaces, which can be tuned to produce multiple functions, making it highly valuable for various applications. The results indicate that the proposed approach is efficient and accurate and provides a promising method for designing reconfigurable intelligent surfaces for future wireless communication systems. [ABSTRACT FROM AUTHOR]

To obtain the VO2 film/CVD diamond-coated tools, the deposition process of CVD diamond coating on the VO2 film surface is investigated in this paper. Firstly, the effect of carbonization treatment on VO2 film is studied. Then, the deposition process of CVD diamond coating on the VO2 film is studied. Finally, it is studied that the change law of the VO2 film/CVD diamond coating system stresses under thermal loading. Results indicate that the CVD diamond coating can be grown on the VO2 film after carbonization and diamond seed crystal treatment. The V6C5 is the most stable material after the carbonization of the VO2 film, and it is used to connect diamond coating and VO2 film. The VO2 film/CVD diamond coating system stress undergoes a sudden change under thermal loading. After the sudden change of stress, the VO2 film/CVD diamond coating system stress is only half of the CVD diamond coating stress. The adhesion of CVD diamond coating is more than 100 N. This study can provide a new idea for the deposition of CVD diamond-coated cutting tools with high bonding performance. [ABSTRACT FROM AUTHOR]

High frequency fatigue behavior of near surface of turbine disk are critical for its application and operation. High frequency indentation fatigue tests of GH4169 alloy under different load amplitudes, frequencies and mean loads at small length scale were conducted, and the dependence of load amplitude, load frequency and mean load on high frequency indentation fatigue property of GH4169 alloy are discussed in this paper. Depth amplitude (ha), mean depth (hm) and depth propagation rate (dh/dN) were employed as evaluation indicators of the indentation behavior. Results show that depth amplitude is only relevant with load amplitude, while mean depth is related to all the adopted influencing factors, ranked in an ascending order as load amplitude, mean load and frequency with a ranking relation of nm1=1.4 < nm2=1.71 < nm3=2.02. Furthermore, a modified Paris law was utilized to reveal the fatigue mechanism, and found the fatigue mechanism is dominated by intrinsic mechanism under the influence of mean load and load amplitude, while for the influence of frequency, the fatigue mechanism is governed by extrinsic mechanisms. Combined with SEM results and three-dimensional morphology analysis, it can be deduced that dislocation movement mode in high frequency indentation fatigue is dislocation slip. [ABSTRACT FROM AUTHOR]

The wettability of the membrane surface is very important for the separation of oil-in-water emulsion. In this paper, the hydrophilic NH2-CAU-1 was added to the membrane surface by interfacial polymerization, which greatly improved the separation efficiency of oil-in-water emulsion. The effect of the amount of NH2-CAU-1 on the separation efficiency of TFN membrane was studied, and it was determined that TFN-1 membrane had ultra-high separation efficiency of oil-in-water emulsion (> 97.60%). TFN-1 membrane has a high underwater oil contact angle (higher than 139.53°), resulting in excellent oil adhesion resistance on the membrane surface. The universality and cycling performance of TFN-1 membrane were tested, and UWOCA had good stability under strong acid, strong base and different NaCl concentrations, and the separation efficiency did not change significantly after 8 cycles. The results show that TFN-1 membrane has excellent performance in separating oil-in-water emulsions and has broad application prospects in separating oil-in-water emulsions stabilized by surfactants. [ABSTRACT FROM AUTHOR]

Characteristics of dislocations induced by Vickers indentation in hydride vapor phase epitaxy GaN were investigated. Dislocations in a rosette pattern have a 11 2 ¯ 3 / 1 1 ¯ 00 slip system and are mobile under both electron beam and multiphoton excitation. They act as nonradiative recombination sites in the range of 370–560 nm. Dislocations in a flower pattern have a 11 2 ¯ 0 / 0001 slip system and are immobile under excitation. The straight part and loop part of dislocations in a flower pattern are radiative at 440 nm and nonradiative in the range of 370–560 nm, respectively. Dislocations in a triangular area are radiative at 386 nm. The origin of the light emitting property of the straight part in a flower pattern is discussed as the transition between partial dislocations dissociated from an a-type dislocation on (0001). Recalculated dislocation pattern size ratios are well matched with experimentally estimated ones by replacing the dislocation type in a rosette pattern described in the earlier literatures (a-type) with estimated dislocation types in this paper (c + a-type). [ABSTRACT FROM AUTHOR]

The introduction of nanotechnology in the food industry has created several opportunities for this sector. Several recent advancements in food packaging use nanotechnology to enhance the function and quality of the packaging materials. This review focuses on how various nanomaterials used in different packaging materials help in maintaining the quality and shelf life of the food product. Several applications of nanomaterials in food packaging such as the use of silver nanoparticles as powerful antibacterial agents, polymer/clay nanocomposites as high barrier packaging materials, and nanosensors were mentioned here. The advances in food nanopackaging, including improved, active, smart, and bio-based packaging, were also discussed. The bio-based packaging offers a substitute for the most widely used non-degradable polymer substances. This review paper aims to highlight some of the most recent technological developments with the use of nanotechnology in the food industry and to indicate some of the many potential future research directions. [ABSTRACT FROM AUTHOR]

This research paper presents a technology for preparing hydrogels based exclusively on natural materials (alginate, carboxymethylcellulose and starch) as carriers of micronutrients (Cu, Mn and Zn). Experiments were performed to select the hydrogel matrix components, including a comparison of the viscosity and density of sodium alginates purchased from different manufacturers, as well as the effect of additives (carboxymethylcellulose and starch) on the swelling properties and strength of the structures. Finally, a solution containing 2 wt% alginate, 2 wt% carboxymethylcellulose and 10 wt% starch was used to prepare reproducible spherical hydrogels. The influence of hydrogel preparation methods on their sorption capacity and strength (either direct dropping into micronutrient solution or two-step, i.e., dropping into calcium chloride and later sorption in micronutrient solution) was also explored. The study revealed that the enrichment of hydrogels with micronutrients by the two-step method is slower, but the structures have better mechanical strength (Young's modulus more than 4 times higher) than those enriched by the one-step method. A series of analyses (FTIR, TGA, XRD and TEM) showed that obtained hydrogels have a semicrystalline structure, are thermally stable and mainly involve carboxylic acid groups in the enrichment process. The effectiveness of the designed hydrogel matrix for the slowed release of micronutrients has been preliminarily proven in winter wheat germination tests. The best results (12.2 cm stem length and 47.9 cm roots) were obtained for the group, where hydrogels were applied at a dose equivalent to 50% of the wheat's Cu, Mn and Zn requirements. [ABSTRACT FROM AUTHOR]

Calcium cobaltate (Ca3Co4O9) is an excellent thermoelectric (TE) material that can realize the mutual conversion between thermal and electrical energy based on the Seebeck effect. Compared with other ceramic TE materials, Ca3Co4O9 has the advantages of good oxidation resistance and high-temperature stability, but its electrical conductivity is low, making its TE properties insufficient. Thus, the figure of merit (ZT) of Ca3Co4O9 materials cannot meet the actual production needs, so it is necessary to modify the Ca3Co4O9 to improve its TE properties. By doping with other elements, the carrier concentration in the Ca3Co4O9 system will increase, and the phonon scattering by impurity atoms will occur, whereas the scattering of electron is rather weak. Thus, the electrical conductivity of the material increases and the thermal conductivity decreases. Therefore, the TE properties of the Ca3Co4O9 material will be improved. This paper summarizes the methods of doping with other elements to improve the TE properties of Ca3Co4O9 materials in recent years, mainly including Ca site doping, Co site doping, and Ca and Co site double doping with various elements, including alkali (earth) metals, transition metals, rare earth metals, and even main group metals and non-metals. Furthermore, the current problems and development trends of the doping modification of Ca3Co4O9 materials are discussed to provide a theoretical basis for the further development and utilization of Ca3Co4O9 TE materials. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced thermoplastic composites (CFRTPs) are widely used in industrial manufacturing due to their excellent mechanical properties, and the joining of lightweight metal/CFRTP hybrid structure has gained more attention. Ultrasonic welding is a promising method for achieving metal/CFRTP dissimilar joining. In this study, 6061 aluminum alloy and carbon fiber-reinforced polyamide-66 (CF/PA66) were ultrasonically welded by preparing a PA6 coating on the surface of aluminum sheet as an interlayer. This paper investigates the effects of welding parameters on the joint mechanical property. Optimized process parameters (welding force 600 N, amplitude 60% and welding time 0.6 s) are determined by experiments. The effects of the thickness and crystallinity of the PA6 coating on the joint strength are investigated. The results show that there exists an optimal coating thickness that maximizes the joint strength. Low crystallinity of the coating contributes to high joint strength. Mixed failure mode (adhesive failure, substrate failure and cohesive failure) is observed based on the analysis on the fracture surface. [ABSTRACT FROM AUTHOR]

Self-powered photodiodes based on the photovoltaic effect have garnered substantial attention, addressing the pressing need for a new generation of optoelectronic nanodevices. However, conventional junction-type self-powered photodetectors exhibit performance limitations. In this paper, we propose a high-speed phototransistor incorporating a dual van der Waals heterostructure (vdWH) of ReS2/WSe2/Te. The device demonstrates a low dark current level (10−14 A). In self-powered mode, the device exhibits exceptional optical response at 785 nm laser (10 µW), achieving a responsivity of 13.98 mA·W−1, a detectivity of 1.65 × 1011 Jones, and an on/off ratio of up to 106. Additionally, the device displays a fast rise/fall time of 7.2/7.14 µs at 532 nm laser (10 µW). Energy band analysis and carrier transfer studies reveal that the floating heterojunction at the bottom of the dual vdWH effectively increases the photogenerated carriers in the top vdWH layer as well as reduces their recombination. This photodetector design provides a practical pathway toward the development of high-performance phototransistors. [ABSTRACT FROM AUTHOR]

Composites are popular in construction engineering due to their low water absorption, good chemical and corrosion resistance, lightweight, high specific strength, high specific modulus, and low thermal conductivity. The flame retardancy (FR) of composite materials has increasingly become the focus of attention in the field of construction engineering. With growing awareness of personal and property safety, a wide range of flame-retardant composites has been developed over the years through research and development. The FR of an unmodified polymer composite is not optimal, and therefore, many innovative methods for making more advanced flame-retardant materials have been developed. The aim of this review is to provide detailed literature on flame-retardant composites. The structure of this paper consists of evolution of flame-retardant materials, their manufacturing techniques, flame-retardant composites, their properties and characterization, applications, and challenges related to of FR composites. The primary focus of this review is to analyze the mechanism of fire retardancy and to summarize the preparation of flame-retardant polymer materials by adding various flame-retardant agents. [ABSTRACT FROM AUTHOR]

This paper presents experimental ductile fracture data for 2139-T8 aluminum alloy under various stress states for the ultimate purpose of probing the fracture envelope as a function of stress triaxiality and normalized Lode angle. A new ductile fracture model is also proposed and validated by experimental data, along with the evaluation of existing ductile fracture models. The data extracted from published literature on 2024-T351 aluminum alloy was also used as an additional experimental data set for validation. An extensive experimental program was implemented to produce data in a wide range of stress states, including tensile tests (with round smooth, round notched, and plate specimens), torsion, compression (with round smooth and round notched specimens), and shear-compression experiments (two different sizes). The combined effects of stress triaxiality and normalized Lode angle were used to define a 3D fracture envelope for fracture strain. A parallel finite element simulation (fine-tuned by the experimental results) has been performed for each experiment to evaluate the evolution of stress triaxiality and normalized Lode angle in the critical section of the specimens with complex geometries. Finally, these results were used to develop two fracture models whose predictions were compared with some of the existing models. [ABSTRACT FROM AUTHOR]