This paper considers the variability in the impact of multi-dimensional
meteorological information on power load in different regions. To
improve the accuracy of load forecasting in the spatial dimension, the
method of spatio-temporal fusion (SF) of multi-dimensional
meteorological information is proposed. The Copula theory is applied to
analyze the nonlinear coupling of meteorological information such as
wind speed, rainfall, temperature, and sunshine intensity from multiple
meteorological stations with the power load and to achieve
spatio-temporal fusion. In the time dimension, the core parameters of
the variational mode decomposition (VMD) are improved by the marine
predators algorithm (MPA). The weighted permutation entropy (WPE) is
used to construct the MPA-VMD fitness function for the adaptive
decomposition of the load sequence. In addition, the input sets of the
LSTM model and MPA-LSSVM model are constructed by combining each
component of the time dimension and each meteorological information of
spatial dimension to obtain the prediction results of each component.
The prediction model corresponding to each component is selected
according to the evaluation index, and reconstructed to obtain the
overall prediction results. The analysis results show that the proposed
forecasting method is better than the traditional forecasting method and
effectively improves the accuracy of power load forecasting.
The 3D model of machine tool column of NC gear shaper is created in Pro/E. This model is imported into the HyperWorks by STEP file. The column structural static stress and deformation, the five-step modal natural frequencies and mode of vibration are obtained by Hyper Works static and dynamic analysis. Based on the analysis results, this study offers a kind of reference comments for the design and improvement of machine tool column of the gear shaper.
The keyhole arc welding technique has the advantage of improving welding efficiency by utilizing a stable keyhole mode. Accurate understanding of the keyhole effect is necessary to enhance the welding quality. Due to the high temperature and strong arc force involved, the complex gas–liquid–solid interactions in the complete keyhole process need to be explored. In order to fully demonstrate open keyhole mode welding, a three-tier sandwiched model based on multiphysics and multiphase effects was developed. The top layer of the model is filled with plasma arc, which gradually fuses and penetrates through the middle metal layer. Finally, it enters the third layer, resulting in an open keyhole mode. Multiphysics phenomena due to the plasma arc are fully included in the model, and the gas–liquid–solid interactions are calculated by combining the Volume of Fluid technique and the Enthalpy-porous technique. Arc ignition and dynamic open keyhole effect are demonstrated, and an arc discharge is shown from the open keyhole exit. The arc reflection phenomenon is observed as the arc is blocked by the weld pool frontier. The electric current path varies with the welding movement, and most of the current comes from the weld pool frontier. An experiment was conducted to obtain weld pool and keyhole images, which basically agree with the calculated results. Additionally, the calculated open keyhole time and electric potential drops also coincide well with experimental data.
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