The catalytic performance of Mn-tetraarylporphyrins in the highly selective oxidation of primary aromatic amines to azo compounds by Bu4NHSO5

The catalytic activity of Mn(TPP)OAc/imidazole system in the oxidation of aromatic amines using Bu₄NHSO₅ in CH₃CN, provides a rapid and highly selective method for the preparation of symmetrical azoarenes, in high/excellent yield (78–96%) and short time (<5 min). The selectivity of the reaction depends remarkably on both the axial ligand and the nature of the solvent. Electron-deficient anilines are oxidized slowly and yield azoxy arenes as the main product. The presence of an electron-donating group on the phenyl ring of both the aromatic amine and the porphyrin ligand of the catalyst enhances the oxidative reactivity of the amine as well as the catalytic activity of the Mn-catalyst. The high turn over rates obtained for Mn-porphyrin reflect the efficiency as well as the relative stability of this biomimetic catalyst towards oxidative degradation. Some evidences for the participation of an Mn-oxo species as active oxidant in this catalytic process have been obtained.     

An artificial neural network approach to determine the rheological behavior of pickering-type diesel-in-water emulsion prepared with the use of <Emphasis Type="Italic">β</Emphasis>-cyclodextrin

With the use of β-cyclodextrin (β-CD), Pickering-type diesel-in-water emulsions were prepared based on the inclusion complex formed between diesel and β-CD which acted as an emulsifier. By using the artificial neural network (ANN), the rheological behavior of the emulsions was characterized using three input variables: diesel-to-water ratio, β-CD concentration, and shear rate and one-output variable as shear stress. Gradient descent (GD), conjugate gradient (CG), and quasi Newton (QN) were used as three different methods in the feed-forward back-propagation algorithm for network training. Hyperbolic tangent sigmoid and pure linear were the transfer functions used for transforming information between input and output through one hidden layer containing ten neurons. By dividing the experimental data into three sets of training, validation, and testing, the QN method in predicting shear stress was found to have performed better than the other two network learning techniques (R²=0.994 and MSE=0.006).     

A novel Harris hawks’ optimization and k-fold cross-validation predicting slope stability

Engineering with Computers - Stability of the soil slopes is one of the most challenging issues in civil engineering projects. Due to the complexity and non-linearity of this threat, utilizing...     

基于数字信号处理器和IRMCK201的电梯门机伺服系统

介绍了一种基于数字信号处理器(DSP)和IRMCK201的电梯门机伺服系统解决方案。该方案采用IRMCK201实现永磁同步电机电流环和速度环,采用DSP实现速度曲线的生成、与上位机的通信以及其他辅助处理功能。实验证明,该方案具有性能优越、设计简单、开发周期短等优点,具有较好的推广意义。