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The laying process is crucial in using stereolithography (SL) for molding Al2O3 parts. However, most studies focus on the laying process of macroscopic slurry; there needs to be more focus on microscopic exploration. Studying from a microscopic perspective can help us understand the influence of its parameters on droplet spreading and infer the macroscopic changes of the slurry based on the changes in droplet spreading to understand why parameters cause macroscopic changes in the slurry. A pseudopotential model based on Sisko's non-Newtonian behavior in lattice Boltzmann method is proposed to study the spreading process of droplets and validated using wetting characteristics. The previous layers of the platform and the printed solid are investigated to understand the effect of laying velocity on the spreading diameter, the thickness, and the both-sided contact angles. The results indicate that a higher laying velocity leads to a larger spreading diameter, a smaller spreading thickness, and a smaller left contact angle. However, it also increases the contact angle difference between the two sides, leading to uneven slurry. The droplet spreads more unevenly when the previous laying surface is the printed solid. At the same velocity, the droplet spreads with a smaller diameter, thicker thickness, and larger contact angle on the printed solid surface. Therefore, a higher laying velocity in the SL laying process is not recommended, especially when the front layer is a printed solid. Although a higher laying velocity will increase the laying area and reduce laying time, it will cause protrusions at the front edge, and inconsistent laying thickness of the same layer will affect the following photosensitive curing process. The Harris Hawks optimization-generalized regression neural network algorithm is proposed and compared with other common artificial intelligence algorithms to predict the spreading parameters. The comparison shows that the proposed algorithm provides a more stable and accurate prediction of spreading parameters. [ABSTRACT FROM AUTHOR]

The coating process is an essential part of stereolithography technology to mold alumina paste, achieved using a scraper. The characteristics of the scraper (geometry and roughness) are investigated to discover the potential influence mechanism on the coating process. To complete the analysis, the bidirectional gated recurrent unit (BiGRU) optimized by the marine predator algorithm (MPA) is proposed to provide a predicted model for the rheological data instead of the traditional fitting by using the known rheological equations. Then, a pseudo-lattice Boltzmann (pseudo-LB) method is proposed to conduct the coating flow simulation without a specific rheological equation, where the predicted rheological model is applied to obtain the relaxation time for each iteration. Based on the above MPA-BiGRU pseudo-LB method, three geometries and different roughnesses are explored for the coating process. The results indicate that the rectangle geometry suits the large coating speed, and the trapezium geometry is recommended for conditions with the small coating speed. The roughness significantly affects the coating process with the rectangle geometry, and the smoother scraper generates a minor disturbance. However, it is almost ineffective in the cases with trapezium geometry. [ABSTRACT FROM AUTHOR]

The aircraft serving in the marine environment is easy to cause the corrosion of its structure due to the long-term influence of the harsh environment such as seawater and salt mist. In order to improve the corrosion resistance of aircraft structure, plasma spraying and laser cladding were used to prepare Fe-based amorphous coatings on the surface of 304 stainless steel. The microstructures of the coatings were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and their microhardness was tested using a Vickers hardness meter. The corrosion behavior of Fe-based amorphous coatings in the simulated seawater environment was studied by potentiodynamic polarization curve measurement and electrochemical impedance spectroscopy. The results showed that the Fe-based amorphous coatings prepared by these two surface technologies have good corrosion resistance, and can reduce the corrosion rate of aircraft structure, so as to ensure the safety of flight operation. [ABSTRACT FROM AUTHOR]

In this paper, AlCoCrFeNi high-entropy alloy composite coatings using the AlCoCrFeNi matrix with Ni-coated-Al2O3 reinforcement were prepared by laser cladding to investigate the effect of Ni-coated-Al2O3 addition on slurry erosion resistance. Microstructure and microhardness of all high-entropy alloy (HEA) composite coatings were characterized by using x-ray diffraction, scanning electron microscope and Vickers hardness measurement. The slurry erosion test was carried out by using an abrasive waterjet method to evaluate the erosion performance of all coatings. The results show that AlCoCrFeNi HEA composite coatings present the typical equiaxed crystal structure with the single body-centered cubic (BCC) phase. After adding the Ni-coated-Al2O3 reinforced powders, the grains of composite coatings are gradually refined with increase in Ni-coated-Al2O3 mass fraction. The average microhardness of composite coatings increases with the increase in the Ni-coated-Al2O3 powder content. The cumulative mass loss of the composite coatings is lower than that of martensitic stainless steel substrate and gradually decreases with the increase in Ni-coated-Al2O3 mass fraction, which proves the addition of Ni-coated-Al2O3 particles can effectively enhance the slurry erosion resistance. Ploughing and micro-cutting are the primary erosion mechanisms of AlCoCrFeNi-x Ni-coated-Al2O3 composite coatings at low erosion angle, while the erosion mechanisms of composite coating material loss are dominated by ploughing and craters at high erosion angle. [ABSTRACT FROM AUTHOR]

BACKGROUND: 3D printing provides a new way of molding chocolate with complex geometrical structures. The screw extruder can efficiently transport the liquid chocolate, which has been adopted to investigate the effect of the profile of the screw flight on the flow. First, the rheological behavior of the liquid chocolate is measured and the Cross equation is demonstrated as the proper rheological model. Then, based on the rheological behavior, an improved lattice Boltzmann method is creatively proposed, for which the effectiveness is validated by the classical Poiseuille flow. Third, the geometrical structure of the screw extruder is analyzed and transformed. The possible changes in the profiles of the screw flights are listed. Finally, the fluid analysis is conducted and the necessary streamlines figures, cloud charts and velocity distributions are obtained. RESULTS: The large dip angle in straight cases has an obvious effect on the velocity distribution and the common flow area. The position of the convex point is the additional important factor, whereas the concave profiles are the most moderate in the proposed cases. CONCLUSION: The changes in the profiles will affect the chocolate flow. The work is significant for extrusion theory in 3D printing. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this study, a copper brazing filler metal coating is fabricated on a 304 stainless steel (304SS) substrate using an electroplating technique. The effect of using electroplated copper brazing filler metal coatings compared to pure copper foil of the same thickness for vacuum brazing of stainless steel joints is investigated. The microstructure and microhardness of the brazed joints are characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM), and a Vickers hardness tester. The shear strength of the brazed joints is measured using an INSTRON 5869 universal testing machine. The results indicate that the electroplated Cu coating is dense, predominantly with a single cubic phase, with a few copper particles aggregating on the surface. Under electroplating conditions of 20 mA cm−2 for 1 h, the coating thickness was 56 μm. The shear strength of the brazed joint with this coating reached a maximum of 333.7 MPa, which is higher than that of a brazed joint with a 60 μm thick copper foil, which exhibits a shear strength of 303.2 MPa. The shear strength of the brazed joints shows an initial increase followed by a decrease as current density and electroplating time increase. This study provides significant technical support for brazing complex shapes or precision components. It suggests a method to simplify the brazing process, reduce production costs, and enhance the strength of brazed joints. [ABSTRACT FROM AUTHOR]

Gastric cancer (GC) presents a significant global health burden, with metastasis being the leading cause of treatment failure and mortality. NAT10, a regulatory protein involved in mRNA acetylation, has been implicated in various cancers. However, its role in GC, especially concerning metastasis and immune interactions, remains unclear. Utilizing multi‐omics data from gastric cancer samples, we conducted comprehensive analyses to investigate NAT10 expression, its correlation with clinical parameters and immune relevance. Bioinformatics analysis and digital image processing were employed for this purpose. Furthermore, in vitro and in vivo experiments were conducted to elucidate the functional role of NAT10 in gastric cancer progression, aiming to provide deeper biological insights. Our findings reveal a significant association between NAT10 expression and various aspects of transcriptional, protein, as well as tumor immunity in GC patients. Additionally, we demonstrated that NAT10 promotes gastric cancer cell proliferation and migration, both in cellular models and in animal studies, suggesting its involvement in early tumor microvascular metastasis. NAT10 emerges as a promising molecular target, offering potential avenues for further research into molecular mechanisms and therapeutic strategies for GC. [ABSTRACT FROM AUTHOR]