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This review emphasizes the evolving need for automated inspection in metal fabrication processes due to the increasing complexity of design advancements over the years. The study explores various defect detection algorithms and evaluates their effectiveness in enhancing the accuracy and reliability of the inspection process. Machine vision plays a crucial role in this context, contributing significantly to the precision of the inspection process in metal fabrication. Its ability to handle complex tasks ensures a thorough assessment of manufactured components. The paper also explores the use of digital image correlation (DIC) as a key tool in quality assurance for metal fabricated products. This technique provides detailed insights, enabling a thorough understanding of structural integrity and defect identification. By integrating insights on automated inspection through defect detection algorithms, machine vision and DIC, this review aims to advance quality assurance methodologies in the ever-evolving field of metal fabrication. [ABSTRACT FROM AUTHOR]

Use of metal matrix composites (MMCs) in automobile and aerospace industries is increasing predominantly since the last few decades, because of their logical amalgamation of properties, principally high strength and low weight. Though selection of matrix and reinforcements are the primary decisive factors of composite properties, the effect of fabrication method on its properties cannot be ignored. Accordingly, this paper accentuates a comprehensive review on different fabrication methods of MMCs as adopted by researchers in open literature. Outcome of the study revealed existence of three broad categories of composite fabrication methods, i.e. liquid state processing, semi-solid processing and solid state processing. However, many researchers have modified these methods suitably to achieve uniformity in reinforcement dispersion and enhanced properties. A case study on squeeze casting route to fabricate and investigate the microstructure and properties of Al 7075 base alloy and nano-TiB2 reinforced Al 7075 MMC is also emphasised in this paper. Results of the case study implied that the fabricated MMC was with very low porosity content (0.106%), near uniform distribution of reinforcements along with some segregated TiB2 regions in its microstructure. The MMC possessed higher mechanical properties (microhardness, tensile strength and compressive strength) than those of the base matrix alloy. [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing (WAAM) is a notable process in metal additive manufacturing (MAM) for the fabrication of metal parts that utilizes economically viable equipment and has high productivity compared to other MAM processes. However, excessive heat accumulation during metal deposition and the cooling method can induce residual tensile stresses and the emergence of defects, which can compromise the geometrical and mechanical integrity of components produced by WAAM. A relatively effective solution to reduce the occurrence of defects and increase the production of high-quality, structurally reliable parts with better surface finishes is to implement temperature control between passes in the WAAM process. This work is aimed at implementing and evaluating active cooling techniques using forced air cooling system (FACS) and half-immersion cooling system (HICS) in WAAM. For this purpose, FACS and HICS systems were implemented and WAAM preforms were produced under different cooling conditions. Visual inspection and geometric and microhardness characterization of the obtained preforms were performed, as well as productivity analysis of the system. The results of the geometric evaluation show little discrepancy between the dimensions of the preforms produced with different cooling techniques, with significant reductions in manufacturing time using FACS and HICS compared to natural cooling (NC), by approximately 73.1% and 87.1%, respectively. Similarly, the impact of the cooling mode on the formation of porosities is discernible. When the FACS system is employed, these defects are more susceptible to generation. The transverse hardness profiles of the three preforms exhibited comparable trends along the manufacturing direction. However, the manufactured system used by HICS exhibited higher average hardness values. [ABSTRACT FROM AUTHOR]

Multi‐component deoxyribozymes (MNAzymes) have shown extraordinary potential in precise gene therapy in vitro, however, the in vivo application is limited by complicated delivery systems. Herein, a novel DNA‐metal binding mechanism is discovered, and metal‐nucleic acid frameworks (MNFs) are built composed of MNAzymes and metal ions, which enable the carrier‐free self‐delivery of MNAzymes. Metal ions have a high affinity to DNA, however, the binding of metals with DNA at 20–30 base pair long (that normally a MNAzyme has) to form MNF structure is challenged by stringent high‐temperature synthesis conditions, poor stability of the products, and lack of targeting capabilities. While, it is discovered that through folding and entanglement of the MNAzyme with an aptamer tail, and prolonging the sequence to 71 base pair, the metal MNAzymes binding is significantly improved and stabilized to MNF structure even at room temperature. Moreover, the aptamer tail also endows MNFs with targeting capabilities. As proof of concept, a carrier‐free Ca/MNAzyme delivery system at room temperature, loaded with the model imaging protein BSA‐Cy5 is synthesized. This system can effectively target Her‐2 positive gastric cancer cells with the Her‐2 responsive aptamer tail and initiate dual gene regulation, thereby inducing energy depletion in cancer cells. [ABSTRACT FROM AUTHOR]

Wire-based additive manufacturing (AM) is at the forefront of complex metal fabrication because of its scalability for large components, potential for high deposition rates, and ease of use. A common goal of wire directed energy deposition (DED) is preserving a stable process throughout deposition. If too little energy is put into the deposition, the wire will stub into the substrate and begin oscillating, creating turbulence within the meltpool. If too much energy exists, the wire will overheat, causing surface tension to take over and create liquid drips as opposed to a solid bead. This paper proposes a computer vision technique to work as both a state detection and event detection system for wire stability. The model utilizes intensity variations along with frame-to-frame difference calculations to determine process stability. Because the proposed model does not rely on machine learning techniques, it is possible for an individual to interpret and adjust as they see fit. The first part of this paper describes creation and implementation of the model. The model's capability was then evaluated using a 1D laser power experiment, which generated a wide range of stability states across varying powers. The model's accuracy was evaluated through 3D geometry data gathered from the experimentally deposited beads. The model proved to be both capable and accurate and has potential to be used as a real-time control system with future work. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is a rapidly developing technical field that is becoming an irreplaceable tool to fabricate unique complex-shaped parts in aerospace, the automotive industry, medicine, and so on. One of the most promising directions for AM application is the design and production of multi-material components with different types of chemical, structural, and architectural gradients that also promote a breakthrough in bio-inspired approaches. At the moment there are a lot of different AM techniques involving various types of materials. This paper represents a review of extrusion-based AM techniques using metal-polymer composites for structural metal parts fabrication. These methods are significantly cheaper than powder bed fusion (PBF) and directed energy deposition (DED) techniques, though have a lower degree of part detail. Thus, they can be used for low-scale production of the parts that are not rentable to produce with PBF and DED. Multi-material structures application in machinery, main aspects of feedstock preparation, the subsequent steps of extrusion-based 3D printing, and the following treatment for manufacturing single-metallic and multi-metallic parts are considered. Main challenges and recommendations are also discussed. Multi-metallic extrusion-based 3D printing is just a nascent trend requiring further wide investigation, though even now it shows pretty interesting results. [ABSTRACT FROM AUTHOR]

Fused Filament Fabrication (FFF) is one of the most popular extrusion based metal Additive Manufacturing (AM) Technologies, which has unique advantages in the rapid prototyping of thermoplastic materials, enabling the fabrication of metal parts with low mechanical anisotropy and no residual stress. However, the mechanical properties and dimensional accuracy of FFF printed parts are susceptible to changes in various printing parameters, which affects the FFF application in large-scale manufacturing. This study experimentally studied the effect of various printing parameters namely layer thickness (0.1, 0.2, 0.3, and 0.4 mm), raster angle (0°, 90°, + 45°/−45°, and 0°/90°), raster width (0.3, 0.35, 0.4, and 0.45 mm), and infill density (70, 80, 90, and 100%) on mechanical properties and dimensional accuracy of 316L stainless steel fabricated by FFF. The results showed that the infill density was the most important factor affecting the mechanical properties, followed by the layer thickness, and it was found that higher values of infill density and lower layer thickness result in better tensile strength. Layer thickness was also the main factor affecting the dimensional accuracy, which increased with the decrease in the layer thickness. [ABSTRACT FROM AUTHOR]

The cadmium manganese sulfide, despite being recognized as a highly efficient photocatalytic semiconductor for hydrogen evolution, faces significant challenges in terms of charge recombination when used solely as a catalyst for photocatalytic hydrogen production. The construction of heterojunction photocatalysts is regarded as one of the effective strategies to enhance the efficiency of photocatalytic hydrogen production. In this work, Zn-doped CdSe was adopted to enhance the photocatalytic active sites of the twinned Mn 0.65 Cd 0.35 S. As results, the photocatalytic hydrogen evolution of Zn–CdSe-1/T-MCS-40 can reach approximately 47447.15 μmol g−1 after 5 h, representing a 15 times increase compared to Mn 0.65 Cd 0.35 S. Besides, the hydrogen evolution rate shows almost no significant attenuation after four consecutive cycles (20 h). The significant achievement can be largely attributed to the successful construction of an S-scheme heterojunction of Zn – CdSe-1/T-MCS-40, which effectively minimized the charge transfer distance and suppressed the recombination of photo-generated electron-hole pairs. Additionally, the incorporation of Zn-doped CdSe significantly expands the response range to visible light, thereby providing a conceptual framework for advancing the design of solar-to-chemical energy conversion and effectively guiding the fabrication of metal sulfide-based photocatalytic heterojunctions. • Zn doping broadens the light absorption range of CdSe. • Zn–CdSe is coupled with T-MCS to form the S-scheme heterojunction. • The photocatalytic rate of Zn–CdSe-1/T-MCS-40 exhibits a 15 enhancement compared to Mn 0.65 Cd 0.35 S. • The separation of photogenerated carrier is accelerated by the construction of S-scheme heterojunction. [ABSTRACT FROM AUTHOR]

Evolutionary selection in nature has led to hierarchical structuring as a fundamental optimization strategy for biological structures, maximizing functional performance while minimizing resource usage. Precise hierarchical organization of natural materials over a wide range of length scales gives rise to unique synergistic properties that could not be achieved by single components. Despite the clear advantages offered by hierarchically structuring matter, mastering hierarchical control based on the current synthetic toolbox is still a challenge. In this review, some recent advancements in the fabrication of hierarchical metal organic framework (MOF) materials are highlighted and the advantages that arise due to different kinds of MOF hierarchy are critically analyzed. The special focus of the review lies in highlighting the applications where MOF hierarchical materials can be most impactful and describing characterization techniques currently at the disposal of scientists for the precise characterization of MOF hierarchical structures across all length scales. Finally, the intent is to inspire reticular chemists to master hierarchical control of MOF materials so as to fully utilize the advantages MOFs offer for various applications. [ABSTRACT FROM AUTHOR]

This study introduces an aluminum transparent heater manufactured with a perforated pattern by using inkjet printing process. The polymeric sacrificial layer was deposited in a periodic dot arrangement by inkjet printing and a aluminum thin film was deposited using a vacuum deposition process. By the ultrasonic punching to remove inkjet‐printed sacrificial layer, the transparent electrode with perforated metal pattern was formed. From the multiphysics simulation, it is investigated that the narrow region of the perforated pattern is efficient to generate Joule heating. The relationship between electrical and thermal properties is investigated by adjusting the spacing of holes in the aluminum grid. Finally, the performance of the fabricated transparent heater is demonstrated that ice cube placed on top of the manufactured transparent heater is removed within 120 s. This ultrasonic punching with inkjet‐printed sacrificial layer is expected to be applicable to various applications. [ABSTRACT FROM AUTHOR]

Strong metal‐support interaction (SMSI) has drawn much attention in heterogeneous catalysts due to its stable and excellent catalytic efficiency. However, construction of high‐performance oxide‐capsulated metal nanostructures meets great challenge in materials thermodynamic compatibility. In this work, dynamically controlled formation of oxide‐capsulated metal nanoparticles (NPs) structures is demonstrated by ultrafast laser plasmonic nanowelding. Under the strong localized electromagnetic field interaction, metal (Au) NPs are dragged by an optical force toward oxide NPs (TiO2). Intense energy is simultaneously injected into this heterojunction area, where TiO2 is precisely ablated. With the embedding of metal into oxide, optical force on Au gradually turned from attractive to repulsive due to the varied metal‐dielectric environment. Meanwhile, local ablated oxides are redeposited on Au NP. Upon the whole coverage of metal NP, the implantation behavior of metal NP is stopped, resulting in a controlled metal‐oxide eccentric structure with capsulated oxide layer thickness ≈0.72–1.30 nm. These oxide‐capsulated metal NPs structures can preserve their configurations even after thermal annealing in air at 600 °C for 10 min. This ultrafast laser plasmonic nanowelding can also extend to oxide‐capsulated metal nanostructure fabrication with broad materials combinations (e.g., Au/ZnO, Au/MgO, etc.), which shows great potential in designing/constructing nanoscale high‐performance catalysts. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) belongs to a unique class of polymers. Different properties of PU such as mechanical strength and biocompatibility can be enhanced by co-polymerizing it with different bio and synthetic polymers. It finds huge applications as micro-reactors for the fabrication of metal nanoparticles (MNPs) owing to the synergistic properties of both polyurethane and fabricated metal nanoparticles. Metal nanoparticles fabricated polyurethane have gained much attention in the last few years. These types of nanocomposites hyphenate the mechanical properties of polyurethane with the high surface-to-volume ratio of metal nanoparticles. Here, this review article briefly evaluates different methods of synthesis of polyurethane-based metal nanocomposites and their characterization via different techniques to evaluate their properties. Applications of these polyurethane based nanocomposite materials have also been described critically in different fields depending upon their catalytic, antimicrobial and antifungal potential. Future directions of these nanocomposite materials have also been described in the field of designing of nano-filters and nano-devices in order to attain environmental remediation and sustainability. [ABSTRACT FROM AUTHOR]

The design of structures and their components requires versatility due to the complexity of the loads that these structures and components are exposed to. Traditional materials generally do not have this feature of versatility and therefore, new materials are needed. Metal matrix composites are metallic materials that are promising to possess the versatility feature. However, the fabrication of these types of materials requires special attention. This paper reviews specifically the fabrication of metal matrix composites through the use of the friction stir processing technique coupled with water. The discussion deals with the fabrication of composites using single-pass and multipass submerged friction stir processing techniques. These fabrication methods still do not receive much attention even though they possess a significant microstructural influence. [ABSTRACT FROM AUTHOR]

The use of pressure to achieve superior properties in metals, especially for use in a range of weaponry, has a long history dating back to the artisans of ancient China and many parts of Asia. Nevertheless, scientific principles were not introduced until the classic experiments conducted by Nobel Laureate Professor Percy Bridgman at Harvard University almost 100 years ago and these experiments led directly to the development of metal processing through the procedure now known as high‐pressure torsion (HPT). This review provides a brief overview of the historical evolution of pressure as a convenient tool in metal‐working and then summarizes the major features associated with the processing of metals by HPT and, more recently, the torsional straining of stacked disks in HPT to produce a range of hybrid materials. Finally, there is a brief report on the development of the relatively new processing procedure of tube high‐pressure shearing (t‐HPS) which may be used for the fabrication of metal matrix composites. [ABSTRACT FROM AUTHOR]

Liquid metal, as a novel material, has become ideal for the fabrication of flexible conductive fibers and has shown great potential in the field of biomedical sensing. This paper presents a comprehensive review of the unique properties of liquid metals such as gallium-based alloys, including their excellent electrical conductivity, mobility, and biocompatibility. These properties make liquid metals ideal for the fabrication of flexible and malleable biosensors. The article explores common preparation methods for liquid metal conductive fibers, such as internal liquid metal filling, surface printing with liquid metal, and liquid metal coating techniques, and their applications in health monitoring, neural interfaces, and wearable devices. By summarizing and analyzing the current research, this paper aims to reveal the current status and challenges of liquid metal conductive fibers in the field of biosensors and to look forward to their development in the future, which will provide valuable references and insights for researchers in the field of biomedical engineering. [ABSTRACT FROM AUTHOR]

To compare the production efficiency of selective laser sintering (SLS) to traditional casting for the fabrication of metal prosthodontic frameworks in a prospective pilot evaluation in a hospital prosthodontic laboratory setting. Materials and Methods: The time taken to complete each of the identified stages in the production of 50 removable partial denture frameworks made using either SLS (n = 25) or casting (n = 25) workflows was measured. The mean time for production was calculated for each workflow, and the difference was tested for statistical significance. Results/Conclusion: The results indicate that an SLS workflow may be more time-efficient, and further cost-effectiveness research is indicated. [ABSTRACT FROM AUTHOR]

Laser‐induced forward transfer is a contactless, nozzle free process which enables accurate, precise and fast development of 3D structures. However, a number of shortcomings such as shockwave generation, poor adhesion to receiver substrates and uniform depositions limit LIFT to be utilized. Therefore, this research tends to put forward easy and effective solutions for successful mitigation of the LIFT limitations. Receiver surface modifications and low‐pressure conditions are introduced through laser surface texturing (LST) and a vacuum pump. A number of textures and orientations are investigated for determining the optimal copper (Cu) deposition. Furthermore, utilization of the same laser system for LST enables the manufacturing process cost and time effective. In addition to Cu depositions, additive layers of silver (Ag) and platinum (Pt) are deposited. Finally, Ag and Pt micropillars are fabricated on their respective additive layers leading to formation of Cu‐Ag and Cu‐Pt alloys structure. Subsequently, electrical and material characterizations are made to validate for potential applications. Experimental evidence shows greater adhesion with electrical properties for LST‐based LIFT in low pressure conditions. Finally, an energy analysis is performed based on theoretical and finite element methods (FEM) to gain greater insights into mechanics of the LIFT process. [ABSTRACT FROM AUTHOR]

The roll‐to‐roll (R2R) process for fabricating elastic substrates is essential for the social implementation of next‐generation stretchable devices with soft interfaces. In recent years, there is a growing demand for soft heterostructures with multiple monolithically patterned organic materials. However, a continuous processing technique for substrates with heterostructures patterned using highly stretchable wiring has not yet been developed. Conventional manufacturing methods for stretchable electronics lack production capacity. This study introduces an R2R‐based method for the continuous production of multilayered substrates composed of various elastic materials, integrated with liquid metal (LM) wiring, suitable for stretchable electronics. Continuous fabrication of polymer films is achieved with pattern areas as small as 0.78 mm2, using three different polymers varying in hardness. The R2R coating process, paired with liquid metal wiring dispensing printing, allows for the creation of lines as fine as 140 microns. This process supports the batch production of 15 stretchable hybrid devices at a time and enables the creation of large‐area devices up to 400 cm2. The fabrication technique developed herein holds promise for the future manufacturing of not only stretchable electronics but also cutting‐edge soft electronics like smart packaging. This is expected to be a factor leading to the commercialization of stretchable electronics. [ABSTRACT FROM AUTHOR]

This study is centered on the analysis of composite component additive manufacturing, via fused filament fabrication (FFF), comprising of 316L stainless steel particles in a polymer matrix. It examines the impact of several process factors of FFF, including extrusion speed, layer height, and extrusion temperature, on the density and surface roughness with the goal to minimize porosity. The independent and interaction impacts of these parameters were investigated using a central composite design technique. The technique of analysis of variance was utilized to determine the influence of relevant factors. Regression analysis was used to establish statistical models linking the parameters to green density and surface roughness. The green density was enhanced by reducing the layer height from 0.2 to 0.1 μm and decreasing the nozzle speed from 100 to 20 mm min−1. The surface roughness was improved by using a slow printing speed and minimum layer height. The ideal temperature range for producing favorable results in terms of green density and surface roughness during extrusion was found to be between 235 and 240°C. Significant correlations were found between the parameters and the green density and surface roughness. A genetic algorithm was used as an optimisation tool to determine the thresholds that would provide the highest green density and the lowest surface roughness values. The porosity of the samples generated with the optimized settings was evaluated using microtomography scans. The methodology presented here can be applied to composite and standard polymeric filament printing to determine optimal printing parameters. Highlights: Blend of stainless steel 316L and polymer was used for fused filament fabrication.Printing speed and layer height were the dominating for density and roughness.Height 0.2 mm, speed 20 mm s−1, and temperature 239°C resulted 4.73 g cm−3 density and 21.09 μm roughnessMicrotomography revealed porosity of 1.7% in the optimized sample. [ABSTRACT FROM AUTHOR]

The seamless integration of wearable devices into user‐friendly and cost‐effective healthcare systems requires constituent materials with high degrees of flexibility, stretchability, and adhesive properties without compromising performance during dynamic body movements. This study proposes a liquid metal (LM)‐based multimodal skin‐mountable sensor platform using polydimethylsiloxane tuned for enhanced stretchability and stickiness (sPDMS) to fully leverage the LM's deformability. A highly accessible end‐to‐end fabrication approach is proposed for multifunctional LM sensors from modeling to fabrication and packaging, all achieved without the need for cleanroom facilities or special equipment. The LM‐based facile fabrication process tailored for sPDMS enables an adhesive‐free sensor patch with microfluidic channels of 100 µm width and stretchability up to 100%. A new analytical model provides enhanced estimation on the electromechanical behavior of LM channels compared with existing models. The funnel‐assisted LM filling and tape‐based channel sealing methods enable simple packaging of LM channels with robust external interconnection and direct skin‐interfaced monitoring. The feasibility of this healthcare platform is demonstrated through a multimodal sensor patch with electromechanical and electrophysiological functionalities. The proposed technology addresses current challenges in the cost and complexity of microfabrication, expanding the boundaries of wearable devices for highly accessible and personalized healthcare devices. [ABSTRACT FROM AUTHOR]

AbstractMetal Additive Manufacturing (AM) has attracted significant attention in various industry sectors for large-scale fabrication. However, the limited fabrication efficiency has hindered its practical implementation. In comparison to traditional methods of tuning process parameters, concurrent AM equipped with multiple independently driven lasers is a more promising technique recently developed for the efficient fabrication of large metal parts. To maximize fabrication efficiency while ensuring quality for a multi-laser AM processes, an optimization problem is proposed in this work for multi-laser scanning plan, including scan vector assignment and scheduling. The goal is to minimize the makespan while considering factors that may affect the quality of metal AM parts as constraints. Specifically, the constraints associated with heat-affected zones and the user-specified single-laser scanning area are considered. The optimization model is solved by Deep Reinforcement Learning (DRL), offering the flexibility to include or exclude considerations for different quality/process requirements. Two case studies demonstrate the application of DRL models considering different sets of constraints and compare their performance with two baseline scheduling methods in terms of fabrication efficiency and violation of quality constraints. In addition, the impact of the laser number on operational improvement and the computational cost of the DRL model is also studied. [ABSTRACT FROM AUTHOR]

Laser beam welding (LBW), as a non‐contact process with short cycle times and small heat affected zone, is a key technology for automated metal fabrication. Despite its efficiency, the susceptibility of certain alloys to solidification cracks remains a significant challenge. These cracks emerge in the transition zone between liquid and solid phases during the solidification process. Thermo‐fluid dynamic processes within the melt pool play a crucial role in solidification crack formation during LBW, influencing heat distribution, mass transport, and consequently, the microstructure and mechanical properties of the weld. An in‐depth exploration of thermo‐fluid dynamics within the melt pool, contributes to an improved understanding of the correlations between process parameters and melt pool flow aiming to avoid solidification cracks. Therefore, in situ process investigations were conducted at beamline P07 of PETRA III at the German Electron and Synchrotron (DESY). 1.4404 stainless steel specimen containing an 5 wt.% of tungsten particles, serving as tracer, were additively manufactured using laser powder bed fusion. The tungsten particles are evenly distributed within the samples. High‐speed synchrotron x‐ray imaging of the process zone allowed for detailed in situ analyses. Leveraging the lower x‐ray absorption coefficients of the base steel material compared to tungsten, the particles appeared as dark dots in the images. The experimental setup involved blind welds on the samples, where a portion of the sample was melted by the laser beam, forming a molten pool in the center while the edges remained intact. The uniform distribution of the particles in the sample means that the movement of the particles in the molten pool is overlaid by static particles located in the unmelted edges of the sample. To enhance the observation and tracking of particle movement within the melt pool, the image contrast was optimized, and static particles were filtered out. The resulting images offer a visual representation of thermo‐fluid dynamical flows during LBW, based on the movement of tracer particles. Analysis was performed using an on Hessian blob detection and Kalman filter based tracking tool [1]. The results of this investigation provide valuable insights into the intricacies of thermo‐fluid dynamics during LBW, offering a foundation for the advancement of numerical modeling and simulation tools in the field of LBW. [ABSTRACT FROM AUTHOR]

Gallium (Ga)-based liquid metals (LMs), as an emerging functional material, stand out among many candidates due to their combination of fluidic and metallic attributes, and they have extensively attracted the attention of academic researchers. When fabricated into droplet form, these metals are imbued with many fantastic characteristics, such as a high specific surface area and self-healing properties. Additionally, Ga-based liquid metal droplets (LMDs) achieve higher response accuracy to external stimuli, satisfying the demands of many applications requiring micro-size and precise stimulus-responsivity. Herein, we focus on reviewing the properties of Ga-based LMs and their droplets, the fabrication strategies of metal droplets, their stimulus-response motion under different external fields, and their applications in microfluidic systems, biomedical applications, and micromachines. To further advance the development of responsive Ga-based LMDs, the future outlooks with key challenges related to their further applications are also presented here. [ABSTRACT FROM AUTHOR]

Laser-based powder bed fusion of metals (PBF-LB/M) is the most used additive manufacturing (AM) technology for metal parts. Nevertheless, challenges persist in effectively managing metal powder, particularly in blending methodologies in the choice of blenders as well as in the verification of blend results. In this study, a bespoke laboratory-scale AM blender is developed, tailored to address these challenges, prioritizing low-impact blending to mitigate powder degradation. As a blending type, a V-shape tumbling geometry meeting the requirements for laboratory AM usage is chosen based on a literature assessment. The implementation of thermal oxidation as a powder marking technique enables particle tracing. Blending validation is achieved using light microscopy for area measurement based on binary image processing. The powder size and shape remain unaffected after marking and blending. Only a small narrowing of the particle size distribution is detected after 180 min of blending. The V-shape tumbling blender efficiently yields a completely random state in under 10 min for rotational speeds of 20, 40, and 60 rounds per minute. In conclusion, this research underscores the critical role of blender selection in AM and advocates for continued exploration to refine powder blending practices, with the aim of advancing the capabilities and competitiveness of AM technologies. [ABSTRACT FROM AUTHOR]

Flexible optoelectronics, based on non-planar substrates, hold promise for diverse applications such as wearables, health monitors, and displays due to their cost-effective manufacturing methods. Despite the superior properties of metal oxides, the challenge of processing them at high temperatures incompatible with plastic substrates necessitates innovative annealing approaches. Photonic curing, which delivers microsecond to millisecond broadband (200–1500 nm) light pulses on a sample, emerges as a viable solution. Depending on the optical properties, the targeted film absorbs the radiant energy resulting in rapid heating while the transparent substrate absorbs a minimal amount of light and remains at ambient temperature. The light intensity can be high, but since the light pulse is short, the total energy absorbed by the sample remains low and will not damage the plastic substrate. This perspective explores the innovative application of photonic curing to fabricate flexible metal oxide optoelectronics, including thin-film transistors, metal–insulator–metal devices, solar cells, transparent conductors, and Li batteries, emphasizing the conversion of sol–gel precursors to metal oxides. However, this technique was initially developed for sintering metal nanoparticles to conductive patterns and poses intriguing challenges in explaining its mechanism for metal oxide conversion, especially considering the limited absorption of visible light by most sol–gel precursors. The review delves into UV-induced photochemistry, common flexible metal-oxide optoelectronic components, and non-intuitive distinctions between photonic curing and thermal annealing. By elucidating the distinctive role of photonic curing in overcoming temperature-related challenges and advancing the fabrication of flexible metal oxide optoelectronics, this perspective offers valuable insights that could shape the future of flexible optoelectronics. [ABSTRACT FROM AUTHOR]

This study compares the capital and operating costs of RGB OLED notebook panels patterned by conventional FMM to an alternative photolithographic approach. The results are used to analyze the benefits and challenges of each technology and how those may influence the rapidly growing OLED IT panel market. [ABSTRACT FROM AUTHOR]

Electrochemical discharge machining (ECDM) micro-milling exhibits enormous machining potential in manufacturing metal microstructures. In this paper, a novel sinking ECDM micro-milling using glycol-based electrolyte is proposed for the high-quality fabrication of metal micro-channel structures. Firstly, a novel combined process is developed for the simple and efficient preparation of micro-electrode. With the proposed method, a micro-electrode with 91.1 μm in diameter and 21.2:1 in aspect ratio is successfully machined in 47.2 minutes. Secondly, experimental research on ECDM micro-milling machining of micro-channels in glycol-based electrolyte is carried out using the fabricated micro-electrode. Experimental results show that the machined voltage significantly affects the machining quality of micro-channels. Wear analysis reveals that the bottom geometry of the micro-electrode exhibits equal wear along the axis direction with processing times increasing, and a constant length compensation strategy (1.52 μm/mm) is adopted. Finally, an S-shaped micro-channel without recast layers (Ra 0.093 μm) was successfully fabricated. [ABSTRACT FROM AUTHOR]

Selective loading of spatially separated redox cocatalysts on direct Z-scheme heterojunctions holds great promise for advancing the efficiency of artificial photosynthesis, which however is limited to the photodeposition of noble metal cocatalysts and the fabrication of hollow double-shelled semiconductor heterojunctions. Moreover, the co-exposure of discrete cocatalyst and semiconductor increases the product diversity when both the exposed sites of which participate in CO2 photoreduction. Herein, we present a facile and versatile protocol to overcome these limitations via surface coating of Z-scheme heterojunctions with bifunctional noble-metal-free cocatalysts. With Cu2O/Fe2O3 (CF) as a model heterojunction and layered Ni(OH)2 as a model cocatalyst, it is found that Ni(OH)2 lying on the surfaces of Cu2O and Fe2O3 separately co-catalyzes the CO2 reduction and H2O oxidation. Thorough experimental and theoretical investigation reveals that the Ni(OH)2 outer layer: (i) mitigates the charge recombination in CF and balances their transfer and consumption; (ii) reduces the rate-determining barriers for CO2-to-CO and H2O-to-O2 conversion, (iii) suppresses the side proton reduction occurring on CF, and (iv) protects the CF from component detachment. As expected, the redox reactions stoichiometrically proceed, and significantly enhanced photocatalytic activity, selectivity, and stability in CO generation are achieved by the stacked Cu2O/Fe2O3@Ni(OH)2 in contrast to CF. This study demonstrates the significance of the synergy between bifunctional cocatalysts and Z-scheme heterojunctions for improving the efficacy of overall redox reactions, opening a fresh avenue for the rational design of artificial photosynthetic systems. [ABSTRACT FROM AUTHOR]

For various chronic wounds, bacterial infection is one of the important reasons that hinder their healing. Ion‐crosslinked antibacterial hydrogel dressings based on Ag+, Cu2+ and Zn2+, have made progress in clinical application. However, the toxicity of released metal ions cannot be ignored. Therefore, how to ensure the antibacterial performance of hydrogel dressing while reducing the amount of metal ions is a major challenge for the fabrication of metal ion based antibacterial hydrogel. In this study, a general method is proposed to design cationic ion‐crosslinked hydrogel based on thiourea groups. Taking the hydrogel formed by mixing thiourea modified hyaluronic acid (H‐ANCSN) with Ag+ (HA‐NCSN/Ag+ hydrogel) as an example, the characteristics and application potential of this kind of hydrogel are thoroughly explored. Due to the strong cationic chelation characteristics of thiourea groups, HA‐NCSN/Ag+ hydrogel can gel at low Ag+ concentration and achieve long‐term slow release of Ag+ at stable concentration to balance the antibacterial and biocompatible properties. Moreover, this dynamic thiourea‐Ag+ crosslinking also endowed the hydrogel with the property of "gelation and encapsulation first, injection to cover wound when necessary". Then, the mangiferin self‐assembled nanoparticles are loaded into HA‐NCSN/Ag+ hydrogel as the radical oxygen species scavenger. [ABSTRACT FROM AUTHOR]

This paper describes a novel end-to-end approach for automatic welding-robot programming based on a product-process-resource (PPR) model, for one-of-a-kind manufacturing systems. Traditionally, the information needed to program a welding robot is processed and transferred along the manufacturing organisation's value chain by using several stand-alone digital systems which require extensive human input and high skill to operate. A PPR model is proposed through this research as a platform for storing and processing the necessary information along the value chain seamlessly. Unlike existing approaches which make use of complex algorithms to automatically identify the weldment seams, the approach suggested in this research makes use of information already digitalised by design engineers under the form of ISO 2553:2019 compliant weldment annotations. Hence, the PPR model contains the weldment annotations; it enables the automatic programming of welding robots and reduces human input down to a few minutes only. The applicability in manufacturing of the theoretical concept is demonstrated through technical implementations tested in the laboratory and on the value chain of an engineering-to-order (ETO) industrial partner involved in the metal fabrication industry. The experiments were conducted by creating several products using the proposed artefact. Experiments show that automatic programming of welding robots can be achieved using PPR models. The conducted experiments showed a reduction of about 80% in human input measured in terms of time, when using the proposed solution. The reduction of the human input can free up skilled labour resource which ETO SMEs can reallocate to other tasks. [ABSTRACT FROM AUTHOR]

The article focuses on the comprehensive modernization of the BLS AG's auto shuttle trains, addressing the need for extensive welding expertise due to significant structural interventions. Topics include the welding process from preparation to documentation, the challenges of refurbishing aging train components, and the division of the refurbishment project into manageable work packages to streamline welding tasks and component fabrication.

Design and preparation of bifunctional electrocatalysts with optimized structures and abundant electrocatalytic active sites are significant for hydrogen generation in electrocatalytic water splitting. Herein, we have elaborately prepared Fe-doped CoP nanoparticles encapsulated in porous electrospun carbon nanofibers for bifunctional electrocatalysis on both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The morphologies, components, and properties of the prepared electrocatalysts are influenced by the introduction of a facile air calcination treatment. Porous nanostructure as well as the full conversion of metal active sites are simultaneously achieved. Owing to the protective electrospun carbon nanofibers as well as the abundant exposed active sites, the optimized electrocatalyst exhibits excellent pH-universal HER activities with small overpotentials (99 mV, 159 mV, and 185 mV) at 10 mA cm−2 in acidic, alkaline, and neutral electrolytes, and also presents remarkable OER performance. Moreover, a water electrolyzer cell, using the optimized electrocatalyst as the electrodes, manifests both a high efficiency (1.63 V@10 mA cm−2) and robust stability. This work provides a convenient route for the controllable fabrication of transition metal-based electrocatalysts toward energy conversion. [Display omitted] • Fe-doped CoP nanoparticles anchored in electrospun carbon nanofibers were prepared. • An effective, facile, and controllable air calcination strategy was introduced. • Porous structure and full conversion of metal sites were simultaneously achieved. • The optimized catalyst shows excellent activity and durability for water splitting. [ABSTRACT FROM AUTHOR]

The titanium alloy components utilized in the aviation field are typically large in size and possess complex structures. By utilizing multiple additive manufacturing processes, the precision and efficiency requirements of production can be met. We investigated the hybrid additive manufacturing of Ti-6Al-4V using a combination of cold metal transfer additive manufacturing (CMTAM) and laser metal deposition (LMD), as well as the feasibility of using the CMT-LMD hybrid additive manufacturing process for fabricating Ti-6Al-4V components. Microstructural examinations, tensile testing coupled with digital image correlation and dynamic compressive experiments (by the split Hopkinson pressure bar (SHPB) system) were employed to assess the parts. The results indicate that the interface of the LMD and CMTAM zone formed a compact metallurgical bonding. In the CMTAM and LMD zone, the prior-β grains exhibit epitaxial growth, forming columnar prior-β grains. Due to laser remelting, the CMT-LMD hybrid additive zone experiences grain refinement, resulting in equiaxed prior-β grains at the interface with an average grain size smaller than that of the CMTAM and LMD regions. The microstructures reveal significant differences in grain orientation and morphology among the zones, with distinct textures forming in each zone. In the CMT-LMD hybrid zone, due to interfacial strengthening, strain concentration occurs in the arc additive zone during tensile testing, leading to fracture on the CMTAM zone. Under high-strain-rate dynamic impact conditions, the LMD region exhibits ductile fracture, while the CMTAM zone demonstrates brittle fracture. The hybrid zone combines ductile and brittle fracture modes, and the CMT-LMD hybrid material exhibits superior dynamic impact performance compared to the single deposition zone. [ABSTRACT FROM AUTHOR]

The application of nanotechnology in developing novel thermoelectric materials has yielded remarkable advancements in material efficiency. In many instances, dimensional constraints have resulted in a beneficial decoupling of thermal conductivity and power factor, leading to large increases in the achievable thermoelectric figure of merit ( Z T ). For instance, the Z T of silicon increases by nearly two orders of magnitude when transitioning from bulk single crystals to nanowires. Metal-assisted chemical etching offers a viable, low-cost route for preparing silicon nanopillars for use in thermoelectric devices. The aim of this paper is to review strategies for obtaining high-density forests of Si nanopillars and achieving high-quality contacts on them. We will discuss how electroplating can be used for this aim. As an alternative, nanopillars can be embedded into appropriate electrical and thermal insulators, with contacts made by metal evaporation on uncapped nanopillar tips. In both cases, it will be shown how achieving control over surface termination and defectivity is of paramount importance, demonstrating how a judicious control of defectivity enhances contact quality. [ABSTRACT FROM AUTHOR]

Additive 3D printing technologies dynamically developing at a rapid pace are used in progressive industries. There are several types of additive technologies based on different physical principles: selective laser melting (SLM), electron beam melting (EBM), fused deposition modelling (FDM), lamination object manufacturing (LOM), etc. They are all united by one technological principle -- the production of items through layer-by-layer construction. Similar to traditional shaping methods, each type of additive technology has advantages and disadvantages. The principal materials traditionally used for functional products of various purposes are metals and alloys. Two main technologies for fabrication of metal products are currently well developed worldwide: SLM and EBM. Despite the high accuracy and decent quality of the products obtained by means of these technologies, they have several disadvantages, including the high cost of both the technological equipment and the raw materials used. [ABSTRACT FROM AUTHOR]

Metal fabrication workshops (MFWs) are common businesses in Ugandan cities, and especially those producing metallic security gates, window and door frames (burglar-proof), and balcony and staircase rails. The objective of this study was to comparatively assess the pollution levels and potential health risks of manganese (Mn), chromium (Cr), cadmium (Cd), lead (Pd) and nickel (Ni) in pooled surface soil samples from four 5-, 7-, 8-, and 10-year-old MFWs (n = 28) and a control site (n = 8) in Mbarara City, Uganda. The concentration of the potentially toxic elements (PTEs) was determined using inductively coupled plasma–optical emission spectrometry. Contamination, ecological, and human health risk assessment indices and models were used to identify any risks that the PTEs could pose to the pristine environment and humans. Our results showed that PTE pollution of soils is occuring in the MFWs than at the control site. The mean concentrations of the PTEs (mg kg−1) in the samples were: Mn (2012.75 ± 0.23–3377.14 ± 0.31), Cr (237.55 ± 0.29–424.93 ± 0.31), Cd (0.73 ± 0.13–1.29 ± 0.02), Pb (107.80 ± 0.23–262.01 ± 0.19), and Ni (74.85 ± 0.25–211.37 ± 0.14). These results indicate that the PTEs could plausibly derive from the fabrication activities in these workshops, which is supported by the high values of contamination factors, index of geoaccumulation, and the overall increase in pollution load indices with the number of years of operation of the MFWs. Human health risk assessment showed that there are non-carcinogenic health risks that could be experienced by children who ingest PTEs in the soils from the 7-, 8- and 10-year-old MFWs. The incremental life cancer risk assessment suggested that there are potential cancerous health effects of Cd and Ni that could be experienced in children (who ingest soils from all the four MFWs) and adults (ingesting soils from the 8- and 10-year-old MFWs). This study underscores the need to implement regulatory guidelines on the operation and location of MFWs in Uganda. Further research should be undertaken to investigate the emission of the PTEs during welding operations in the MFWs. [ABSTRACT FROM AUTHOR]

Morphology (size, shape) and structural variations (bonding pattern, crystallography, and atomic arrangements) have significant impacts on the efficacy of the metallic nanoparticles. Fabrication of these metal nanoparticles through green synthesis using plant extracts has increased attention due to their low cost, less hazardous byproducts, and multiple applications. In present study, Eucalyptus globulus extract was used to synthesize silver nanoparticles (AgNPs). Change of color from light brown to reddish brown and UV–visible spectral peak at 423 nm confirmed the formation of AgNPs. The shifting of FTIR spectra peaks indicated the potential role of the functional groups in extract as capping agents. The DLS evaluated the average size and stability of the nanoparticles while the surface morphology, size and the elemental composition of the AgNPs was established by the FESEM and EDX analysis. The SEM images revealed spherical nanoparticles of size ranging from 40–60 nm. Biogenic AgNPs showed better DPPH radical scavenging activity with IC50 (13.44 ± 0.3) as compared to leaves extract with IC50 (10.57 ± 0.2). The synthesized AgNPs showed higher zones of inhibition (ZOI) by well diffusion method against Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. Results of present study highlights the potential benefits of Eucalyptus globulus leaves extract-based AgNPs for various biomedical uses. [ABSTRACT FROM AUTHOR]

The established approach to materials design for additive manufacturing (AM) consists of attempting to reproduce the uniform structures and properties of conventionally processed materials. While this certainly helped facilitate material certification and the rapid introduction of AM technologies in several industries, the opportunity to exploit unique features of specific AM processes to generate spatially varying microstructures–and hence novel materials, remains largely untapped. This work presents a method for manufacturing materials through laser powder bed fusion (LPBF), in which control over the spatial variation in phase composition and mechanical properties is achieved. This technique is demonstrated using 17‐4 precipitation‐hardened stainless steel (17‐4PH), by controlling spatial modulation of energy densities during printing. This results in local control of ferrite/martensite volume fractions, allowing the fabrication of metal/metal architected composites with hard/brittle regions interspersed with soft/tough regions. Local variations of ~20% in tensile strength and ~150% in elongation are achieved, with a spatial resolution of ~100 microns. The approach is general and robust, fully compatible with commercially available LPBF equipment, and applicable to virtually any multi‐phase alloy system. This work shifts the paradigm from attempting to print components with uniform properties to manufacturing alloys with controlled spatial property gradients. [ABSTRACT FROM AUTHOR]

At a certain stage, any large industrial exercise faces the problem of keeping its equipment operational in order to maintain production. Most often, internal maintenance services fill this role, although sometimes the work is outsourced. The approaches adopted at OAO Koks today and during its history are considered. [ABSTRACT FROM AUTHOR]

Four benzaldehyde derivatives [ALD‐1: compound (1), ALD‐2: compound (2), ALD‐5: compound (3), ALD‐6: compound (4)] were taken to investigate their optical band gap by UV‐vis spectroscopy. Semiconducting devices were fabricated using these compounds to study their electrical properties. The current‐voltage (I–V) characteristics graph was obtained. Furthermore, the diode parameters were extracted by conventional methods to analyze the charge transport mechanism. From the dielectric study, a low dielectric constant was observed. Moreover, each compound's mobility and transit time were derived to compare the device performance of benzaldehyde derivatives. [ABSTRACT FROM AUTHOR]

Micro- and nano-sized one-dimensional (1D) metallic materials exhibit tremendous potential in various technological applications such as flexible and transparent electrodes, sensing, and catalysis. However, achieving eco-friendly and large-scale fabrication of diverse 1D metals remains a formidable challenge. The occurrence of A-site whisker growth from MAX phase presents an opportunity for developing an innovative 1D metal fabrication technique. Herein, we investigate the significant role of oxygen in promoting whisker growth from mechanically damaged Ti2SnC MAX phase. Our findings reveal that oxidation of the M-site (titanium) in Ti2SnC phases enhances the formation of atomized tin, which plays a crucial role in tin whisker growth. Furthermore, by employing alternative MAX phase precursors, this technique demonstrates the potential to fabricate 1D metals beyond tin. The diverse A-site elements in MAX phases suggest that this approach could serve as a universal strategy for synthesizing various 1D metallic materials. [ABSTRACT FROM AUTHOR]

We fabricated Cu matrix composites with low thermal expansion and high thermal conductivity using Zn2P2O7-based negative thermal expansion (NTE) filler. Magnesium and aluminum co-doped Zn2−x−yMgxAlyP2O7 exhibits large NTE over a wide temperature range including room temperature. While achieving high density of the phosphate filler using spark plasma sintering and its uniform dispersion by an ultrasonic process, we reduced thermal expansion of the Cu matrix composites and retained their high thermal conductivity. Particularly, the 30 vol. %-Zn1.70Mg0.25Al0.05P2O7/Cu composite had a linear expansion coefficient as low as 5.1 ppm/K at temperatures of 300–400 K. The results reported herein demonstrate that Zn pyrophosphates, which are superior in terms of environmental impact and cost, are effective for controlling the thermal expansion of metals and are expected to support widely diverse engineering applications in the future. [ABSTRACT FROM AUTHOR]

Copper oxide (CuO) films with a thickness of about 1.5 μm having three different morphologies (nanoplate, nanoflake and nanowire) were synthesised by a simple and fast chemical method. Scanning electron microscopy, X-ray diffraction and electrochemical methods were used to analyse the morphology, determine the crystal structure and characterise the electrochemical performance. CuO with a nanowire structure exhibited the best performance. The specific capacitance was as high as 147 F g−1 at a specific current of 0.6 A g−1, while the capacitance remained at 74.4% after 5000 charge/discharge cycles, showing good stability. The simple synthesis described has a low energy consumption and could be used in the fabrication of other metal oxide and flexible hydroxide electrodes. [ABSTRACT FROM AUTHOR]

Agriculture teachers need knowledge and skills in a range of agricultural mechanics topics, such as metal fabrication and power mechanics. Teacher professional development (PD) is one method for improving teacher competence. Both Sorensen et al. (2014) and Yopp et al. (2020) reported differences in teachers' PD needs based on years of teaching experience. Could their findings be consistent on a national level? Moreover, do other teacher demographic factors such as teacher certification route and career phase yield differences in teachers' agricultural mechanics PD needs? Using human capital theory as our guiding framework, the purpose of our study was to examine potential differences in teachers' agricultural mechanics PD needs based on selected teacher demographic factors. We employed Borich's (1980) needs assessment model to structure our study. Further, we used a valid and reliable 72-item instrument and followed Dillman et al.'s (2014) recommendations to collect data from a random sample of teachers from across the United States. One hundred teachers responded to our instrument, yielding a response rate of 27.5%. We found that: (1) there were no statistically significant differences in teachers' agricultural mechanics PD needs based on teacher certification route and (2) there were statistically significant differences in teachers' agricultural mechanics PD needs based on career phase. We recommend that Agricultural Education stakeholders facilitate career phase-differentiated PD opportunities for teachers. Doing so will help to positively impact the teacher competence development process for those who most need it. [ABSTRACT FROM AUTHOR]