Effect of heat treatment on microstructure and mechanical property of Al-10%Mg2Si alloy

After solution treatment at 520 °C for 6 h and subsequent aging at 200 °C for 6 h, eutectic Mg2Si phase in Al-10%Mg2Si alloy transforms from long rod to short fiber-like and spherical morphologies, and a great number of nano-sized β″ particles precipitate in the Al matrix. The fine eutectic Mg2Si phase combined with nano-sized precipitates gives rise to enhanced hardness and high tensile strength of Al-10%Mg2Si alloy (increasing from 186 MPa to 234.6 MPa)

The Impacts of China-US Trade Friction on Global Economy and China’s Economy

Since President Donald Trump provoked China-US trade frictions on the grounds of trade deficits in 2018, the US economic frictions with China have escalated, highlighting the expanding range of goods subject to tariffs, the rising tariff level and the spreading frictions. In particular, provinces play an very important role in carrying the impacts of US tariffs on China. China and the US are major influencers on the global economy. The tariffs affect a country’s economic growth, and change its internal flow of production factors across provinces and even its spatial pattern of economic activities. China’s provincial economies show strong disequilibrium in development level and industrial structure, which directly determines the differences in direct foreign economic and trade ties and role in the division of labor on global value chains. Three scenarios of US imposing tariffs to totally different degrees are designed, under which the impacts on the economic aggregates, imports and exports of China, the US and major trading partners are simulated. According to the simulation results, the soft linkage between the global computable general equilibrium model and China’s multi-provincal input output model is applied to assess the impacts of US tariffs on China’s subnational economy. The impacts of US tariffs on subnational economy are different by province. The direct and total impacts of US tariffs on GDP of eastern coastal provinces including Guangdong, Zhejiang, Jiangsu, Fujian and Shanghai are relatively large. For Anhui, Shanxi, Shaanxi, Inner Mongolia, Gansu and other central and western provinces, the imposition of tariffs indirectly impacts their GDP by affecting the exports of other provinces. Scenario 3 witnesses the hardest impact on provinces’ GDP

Corrosion behavior of Al-Mg2Si alloys with/without addition of Al-P master alloy

Corrosion resistance is an important fact to be considered in practical engineering application of Al-Mg2Si alloys, besides the mechanical properties. So in the paper, corrosion behavior of Al-20%Mg2Si with/without Al-3%P master alloy in 3.5% NaCl solution was investigated. For the Al-20%Mg2Si alloy, Mg2Si acts as anode and corrosion starts from its surface at the initial stage of corrosion process. As the corrosion proceeds, electrochemical polarity converts between Mg2Si and α(Al), which results in the corrosion of Al matrix with the formation of pits. Moreover, after addition of Al-3%P master alloy, Mg2Si transforms from enormous dendrite to fine and uniformly distributing polyhedron, which inhibits the corrosion pits from propagating in Al matrix and enhances the corrosion resistance of Al-20%Mg2Si

Exploring the potential for carrying capacity and reusability of 3D printed concrete bridges: Construction, dismantlement, and reconstruction of a box arch bridge

3D concrete printing technology has enabled the construction of full-scale bridges. However, structural carbon emissions due to higher cement content and limitations of embedded reinforcement have limited its widespread adoption. This paper presents a non-reinforced 3D printed concrete box arch bridge and describes its design, construction, dismantlement, and reconstruction, as well as evaluation of the carrying capacity of reconstructed primary arch ring. The bridge adheres to current technical principles and bridge engineering specifications. By taking into account the mechanical anisotropy and primary stress characteristics of the arch, the design negates the need for reinforcement. The study showcases the reusability and potential carbon emission reduction through block printing, on-site assembly, block removal, and secondary usage. The safety of the reconstructed arch bridge was confirmed through an in-situ load test

Fully Automatic Deep Learning Model for Spine Refracture in Patients with OVCF: A Multi‐Center Study

Background The reaserch of artificial intelligence (AI) model for predicting spinal refracture is limited to bone mineral density, X‐ray and some conventional laboratory indicators, which has its own limitations. Besides, it lacks specific indicators related to osteoporosis and imaging factors that can better reflect bone quality, such as computed tomography (CT). Objective To construct a novel predicting model based on bone turn‐over markers and CT to identify patients who were more inclined to suffer spine refracture. Methods CT images and clinical information of 383 patients (training set = 240 cases of osteoporotic vertebral compression fractures (OVCF), validation set = 63, test set = 80) were retrospectively collected from January 2015 to October 2022 at three medical centers. The U‐net model was adopted to automatically segment ROI. Three‐dimensional (3D) cropping of all spine regions was used to achieve the final ROI regions including 3D_Full and 3D_RoiOnly. We used the Densenet 121‐3D model to model the cropped region and simultaneously build a T‐NIPT prediction model. Diagnostics of deep learning models were assessed by constructing ROC curves. We generated calibration curves to assess the calibration performance. Additionally, decision curve analysis (DCA) was used to assess the clinical utility of the predictive models. Results The performance of the test model is comparable to its performance on the training set (dice coefficients of 0.798, an mIOU of 0.755, an SA of 0.767, and an OS of 0.017). Univariable and multivariable analysis indicate that T_P1NT was an independent risk factor for refracture. The performance of predicting refractures in different ROI regions showed that 3D_Full model exhibits the highest calibration performance, with a Hosmer–Lemeshow goodness‐of‐fit (HL) test statistic exceeding 0.05. The analysis of the training and test sets showed that the 3D_Full model, which integrates clinical and deep learning results, demonstrated superior performance with significant improvement (p‐value < 0.05) compared to using clinical features independently or using only 3D_RoiOnly. Conclusion T_P1NT was an independent risk factor of refracture. Our 3D‐FULL model showed better performance in predicting high‐risk population of spine refracture than other models and junior doctors do. This model can be applicable to real‐world translation due to its automatic segmentation and detection

Effect of barium on the structure and characteristics of Mg2Si reinforced particles Al–Mg2Si–Cu in situ composite

Addition of barium (Ba) in various concentrations is susceptible to cause changes on Mg2Si reinforced particles in Al–Mg2Si–Cu in situ composite. In this study, six samples of the composite with different concentrations of Ba (0.1–0.8 wt%) were prepared. The alteration of Mg2Si structure, phase reaction characteristics and cooling curves behaviour of the composite were investigated via optical microscope, scanning electron microscope (SEM), and computer aided cooling curve thermal analysis (CACCTA). The results depicted that 0.2 wt% exhibit the appropriate concentration of Ba added in order to modify and refine the Mg2Si particles. The skeleton and dendrite shape of Mg2Si particles have been transformed into fine polygonal shape accompanied with decreased in average size from 1178.5 µm of the unmodified particles to 289.1 µm. In fact, the refinement of Mg2Si particles is associated with the increased of nucleation temperature, TN of the respective phase together with the least undercooling, ΔU correspond to the easiness of the particles to be formed prior to its growth. Meanwhile, the decrement of TN respective to other concentrations of Ba indicates the opposite refinement effect of the particles as it became coarser. Besides, the refinement of Mg2Si has induced more nucleation of the particles resulting the increment of the density of particles and better distribution over the composite area. Therefore, the corresponding mechanical and tribological properties of the composite are believed to be improved accordingly