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Twin structures are commonly found in many metals and play a significant role in determining the mechanical properties and corrosion resistance of alloys. However, it is very challenging to observe the formation of twins in melt using traditional methods. In this paper, Fe90Al10 alloy was obtained by the vacuum non-consumable arc-melting method, and the results showed that the grain misorientation in the rapidly solidified Fe90Al10 alloys do not always follow a Mackenzie distribution, there is a peak at 60°, and it is well-known that Σ3 twin boundaries have an misorientation difference of 60°, Therefore, another nucleation method exists at the Σ3 grain boundary. Subsequently, Molecular dynamics simulations of Fe90Al10 alloys have shown that twin formation is sporadic and occurs through heterogeneous nucleation on the surface of previously formed grains, and only Σ3 twin boundaries can be formed in this way, which becomes a way for BCC metals to form twins during solidification, this is also consistent with experimental results, in addition to random nucleation, heterogeneous nucleation also exists during the rapid solidification of Fe-Al ally. Additionally, the aggregation of icosahedral-like (ICO-like) structures present in the under cooled melt leads to the heterogeneous nucleation of twinning and the difference in volume between the twin crystals will affect the subsequent evolutionary process. Therefore, the experimental and simulation results in this study strongly explain a formation mechanism of twins in BCC metals during rapid solidification. [ABSTRACT FROM AUTHOR]

Abnormal grain growth (AGG) involving orientation selectivity during isothermal annealing in non-oriented silicon steels (NGO) was comparatively investigated by quasi-in situ observation. Remarkable abnormal growth of {100} grains occurred in strip-cast NGO after isothermal annealing. Similar AGG tendencies but with relatively small grain size and random orientation were observed in the suction-cast NGO and hot-rolled NGO. The abnormal grain growth process can be divided into three stages: (1) incubation stage where the seed grains germinated; (2) rapid development stage with seed grain growth rate of ~ 1.5 μm/s; (3) perfection stage with grain growth rate of ~ 0.4 μm/s, slowed down by coarse grains and the sheet surface. Grain growth kinetic can be well represented under three segments instead of constant linear regression. The kinetics for normal grain growth and AGG were D = D0 + 4.43 × 10−6t1.789 and D = D0 + 5.95 × 10−6t2.565, respectively. The selective AGG with preferred orientation showed strain dependence. With increase in prior deformation, the trend of AGG weakened and the orientation became more random. Inhomogeneous micro-strain distribution played a key role for initiation and propagation of AGG with preferred orientation in the strip-cast NGO. Sub-rapid solidification and slight deformation during strip casting process typically generated high level of strain inhomogeneity, which acted as an additional driving force to induce AGG by enhanced grain boundary migration. The preferred orientation of AGG may be related to orientation dependence of solidification and grain growth behaviors. [ABSTRACT FROM AUTHOR]

Differential scanning calorimetry (DSC) and confocal scanning laser microscopy (CSLM) were used to investigate the effects of different cooling rates on the solidification and segregation characteristics of Cu-Ni-Si alloy. The microstructures were characterized by electron probe microanalysis and scanning electron microscope. The effects of cooling rate on segregation degree, grain size, solidification temperature and secondary dendrite spacing (λ2) were analyzed, and the correlation function was established. The results show that the characteristic temperature of DSC phase transformation is similar to the characteristic temperature of CSLM in situ microstructure evolution. Increasing cooling rate can reduce segregation degree and refine grains. The relationships between cooling rate and crystallization temperature (TL→S) and secondary dendrite spacing (λ2) with cooling rate are as follows: TL→S = 176 × exp(− v/17.6) + 891 and λ2 = 63 × v−0.236, respectively. The above relations were applied to predict the solidification microstructure characteristics produced by twin-roll strip casting and ingot casting processes, and the predicted results are in good agreement with the experimental values. The advantages of grain refinement and segregation improvement and its optimization mechanism of twin-roll strip casting have been clarified. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnea (OSA) is mainly characterized by chronic intermittent hypoxia (CIH) with multiple brain injuries. Nucleotide oligomerization domain (NOD)–like receptor protein 3 (NLRP3) inflammasome is considered the most important factor inducing and maintaining inflammation. However, the role of NLRP3 and its underlying mechanism in CIH-elicited neuroinflammation remains unclear. We constructed an OSA-related CIH in vivo model and assessed the rats’ cognitive behavior in the Morris water maze. The combination of miR-223-3p and NLRP3 was confirmed by the TargetScan database, double luciferase reporter gene experiment, and RNA immunoprecipitation (RIP) experiment. Western blot and ELISA assay were used to analyze the effects of miR-223-3p targeting NLRP3 on the expression of pyroptotic or inflammatory factors in vivo in CIH rats. Severe cognitive impairment was observed in rats at week 6 post-treatment, with increased inflammatory factors in the blood and hippocampus, heightened NLRP3 expression, and low miR-223-3p levels. And the good binding activity of the two was confirmed by dual luciferase reporter and RIP experiments. Next, we found that silencing NLRP3 or overexpression of miR-223-3p in the CIH model could improve cognitive deficits and reduce the level of proinflammatory factors and pyroptosis factors in rats. Finally, based on silencing NLRP3 or overexpression miR-223-3p, we confirmed that there was a regulatory relationship between miR-223-3p and NLRP3. Our results suggested that the NLRP3/ miR-223-3p axis played a role in attenuating CIH-induced neuroinflammation. [ABSTRACT FROM AUTHOR]

The hot tensile deformation properties and microstructure evolution of high purity C71500 cupronickel alloy at 1 023–1 273 K and 0.000 1–0.1 s−1 strain rates were studied by uniaxial hot tensile deformation method. Based on the experimental data, the flow behavior, microstructure and fracture characteristics of the alloy were analyzed after considering the influence of different deformation parameters. The relationship between microstructure and high temperature (T⩾1 023 K) plasticity is discussed, and the fracture mechanism is revealed. The relationship between strain rate sensitivity coefficient and stress index and plastic deformation is discussed. The constitutive equation of the alloy is established by Johnson-Cook model. Based on the dynamic material model, the energy dissipation model is established, and Prasad's instability criterion based on Ziegler's expected rheological theory is used to predict the unstable region in the processing map. Processing map in hot tensile is analyzed to provide theoretical basis for different processing technology. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the efficacy of eight different surgical treatments based on maxillomandibular advancement (MMA), which has emerged in recent years, for adult obstructive sleep apnoea (OSA) patients. Methods: The literature was searched from January 2010 to May 2020 for studies of adult OSA patients with different types of MMA procedures to perform a network meta-analysis. The outcomes were changes in the apnoea–hypopnoea index (AHI), the lowest pulse oxygen saturation (SpO2 min) and the Epworth Sleepiness Scale (ESS). Treatment hierarchy was summarized according to the rank charts. Results: Eight studies were included and encompassed a total of 227 adult patients diagnosed with OSA. Among them, 225 patients underwent combined surgery or simple MMA surgery, including modified maxillomandibular advancement (MMMA),counterclockwise maxillomandibular advancement (CMMA), drug-induced sleep endoscopy and maxillomandibular advancement (MMA + DISE), transoral robotic surgery and maxillomandibular advancement (MMA + TORS), uvulopalatopharyngoplasty (UPPP), maxillomandibular advancement and uvulopalatopharyngoplasty (MMA + UPPP), uvulopalatopharyngoplasty with uvula preservation and maxillomandibular advancement (MMA + HUPPP); MMA consisting of Le Fort I osteotomy and bilateral inverted-L osteotomy (ILOs), genioplasty and iliac bone grafting; and MMA consisting of Le Fort I osteotomy, bilateral sagittal split ramus osteotomies and genioplasty. The results showed that the most effective surgical treatment is MMA + HUPPP [− 56.79 (WMD); 95% confidence interval (CI): − 113.02 to − 3.33] (P < 0.00001), which was far superior to other approaches. Conclusion: MMA combined with HUPPP had the highest efficacy. The MMA consisted of Le Fort I osteotomy, bilateral sagittal split ramus osteotomies and genioplasty; CMMA and MMA + TORS are likely also great choices. [ABSTRACT FROM AUTHOR]

The isothermal compression tests of C71500 copper-nickel alloy at different temperatures (1 073–1 273 K) and strain rates (0.01–10 s−1) were carried out on Gleeble-3500 thermo-mechanical simulator. The real stress-strain data were obtained. On the basis of dynamic material model, the power dissipation was established. The peak efficiency of the power dissipation is 57%. At the same time, Prasad's, Murty's and Babu's instability criteria based on Ziegler's expectant rheology theory, and Gegel's and Malas's instability criteria based on Lyaponov's function theory, were used to predict the unstable regions in the processing map. The maximum entropy generation rate and large plastic deformation principle are more in line with the hot deformation process of C71500 alloy, so the accuracy of Prasad's instability criterion is much better. According to the obtained macro-crack and micro-metallographic structure morphologies, the temperature range of 1 098–1 156 K and the strain rate range of 2.91–10 s−1, and the temperature range of 1 171–1 273 K and the strain rate range of 0.01–0.33 s−1 are more suitable for the processing area of C71500 alloy. The accuracy of the above conclusions were verified by the forging of materials and the analysis of hot piercing tubes. The significance of this paper is to provide theoretical basis and technological conditions for hot-press processing of C71500 alloy. [ABSTRACT FROM AUTHOR]

The effect of rolling temperature on the evolution of microstructure, texture, and magnetic properties of ultra-low-carbon grain-oriented silicon steel was studied in strip-casting process. Dynamic strain-aging (DSA) behavior was observed during warm rolling in the temperature range of ~ 200 to 400 °C based on the fact that majority of the inhibitor elements remained in solution during the strip-casting process. Considering the initial coarse grains with strong {100} fiber prior to rolling, the cold-rolled specimen exhibited pronounced α-fiber and weak γ-fiber texture. However, intense shear bands and high stored energy regardless of the orientation were obtained in the warm-rolled specimens at the DSA temperature, accompanied by weak α-fiber and strong γ-fiber texture. While homogenous microstructure with lower stored energy was observed in the case of high temperature, the differences in shear bands and stored energy governed by the rolling temperature were strongly related to the extent of DSA effect, which is attributed to distinct characteristic of rolling and recrystallization texture. After recrystallization annealing, fine-grained homogeneous microstructure with strong Goss and γ-fiber texture was obtained at the DSA temperature, while relatively random texture with much more α-fiber and θ-fiber components was observed in the case of high temperature. The microstructure and texture of primary annealed sheets exhibited sufficient Goss grains and favorable surrounding matrix with pronounced γ-fiber texture, which was responsible for the perfect secondary recrystallization annealing in the warm-rolled specimens at the DSA temperature. The present study suggests that texture optimization of strip-cast grain-oriented silicon steel can be achieved by warm rolling in the appropriate temperature range, with improved magnetic properties. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (GNP) possess distinctive physical properties, making them a remarkable material for a wide range of engineering applications. Nonetheless, the existing higher-order theories documented in the literature may not effectively predict the natural frequencies of composite beams that incorporate GNP-reinforced piezoelectric layers. This limitation arises from the electromechanical coupling effects and the pronounced variability in material properties at the interfaces between layers. To overcome these limitations, this study proposes a refined beam theory specifically designed to examine the vibrational behavior of composite beams embedded with GNP-reinforced piezoelectric layers. By enforcing the continuity of interlaminar stresses and incorporating the free-surface conditions for interlaminar shear stresses, the formulation eliminates the dependence on layer-specific unknown variables, leading to a simplified yet accurate displacement field. In contrast to earlier higher-order theories, the current model introduces a refined interlaminar shear stress field incorporating the effects of electromechanical coupling. By utilizing Hamilton's principle, the enhanced shear stress field is incorporated into the governing equations of motion, which leads to a notable improvement in the prediction of natural frequencies for piezoelectric sandwich and laminated beams. Key results show that the proposed model achieves deviations below 3% compared to exact solutions, while existing models exhibit errors exceeding 280%. Additionally, geometric parameters such as the length-to-thickness ratio and layer thickness significantly influence natural frequencies, whereas the GNP volume fraction and electrical boundary conditions have minimal impact. The proposed theory's effectiveness is demonstrated through exact solutions and comparative studies with other models. The results reveal that the proposed theory offers superior accuracy in predicting natural frequencies compared to conventional higher-order models for composite beams. Moreover, a parametric analysis is performed to explore the influences of various key parameters on the vibration properties of smart composite beams with GNP reinforcements. [ABSTRACT FROM AUTHOR]