The use of nested desirability functions and quality indices for multi-response robust parameter design problems

A multi-response robust parameter design (RPD) problem-solving technique based on desirability functions is presented in which the means and variances of all responses are placed on a level playing field. The proposal allows a decision maker to integrate their preferences for the individual means and variances. It is shown that the ensuing operating point is a system setting that produces a mutually robust set of responses. In addition, this article offers an approach to assess several RPD strategies via quality indices. The measures presented here allow for a more knowledgeable and comprehensive evaluation of the competing RPD strategies.     

Cooperative learning neural network output feedback control of uncertain nonlinear multi-agent systems under directed topologies

Without assuming that the communication topologies among the neural network (NN) weights are to be undirected and the states of each agent are measurable, the cooperative learning NN output feedback control is addressed for uncertain nonlinear multi-agent systems with identical structures in strict-feedback form. By establishing directed communication topologies among NN weights to share their learned knowledge, NNs with cooperative learning laws are employed to identify the uncertainties. By designing NN-based κ-filter observers to estimate the unmeasurable states, a new cooperative learning output feedback control scheme is proposed to guarantee that the system outputs can track nonidentical reference signals with bounded tracking errors. A simulation example is given to demonstrate the effectiveness of the theoretical results.     

中央通过《关于设立知识产权法院的方案》

6月6日，中央全面深化改革领导小组第三次会议召开，会议审议通过了“关于设立知识产权法院的方案》等方案。     

Minimization of the Ohmic Loss of Grooved Polarizer Mirrors in High-Power ECRH Systems

A set of two corrugated polarizer mirrors is typically used in high-power electron cyclotron resonance heating (ECRH) systems to provide the required polarization of the ECRH output beam. The ohmic losses of these mirrors can significantly exceed the losses of plane mirrors depending on the polarization of the incident beam with respect to the orientation of the grooves. Since polarizer mirrors incorporated into miter bends of a corrugated waveguide line are limited in size, active water cooling can become critical in high-power cw systems like the one for ITER. The ohmic loss of polarizer mirrors has been investigated experimentally at high power. A strategy to minimize the losses for given mirror geometries has been found.     

Influence of Grain Refinement on Slurry Formation and Surface Segregation in Semi-solid Al-7Si-0.3Mg Castings

This study aims to evaluate the effect of grain refinement on slurry formation and surface segregation in semi-solid castings produced by the Rheometal™ process. The effect of two grain refiners, Al-8B and Al-5Ti-1B, on the slurry α-Al grain size, shape factor and solid fraction was evaluated. The results suggest that the addition of a grain refiner can affect the solid fraction obtained in the Rheometal^TM process and, consequently, reduce the solute content near the casting surface. Grain refiner addition resulted in a larger fraction of α-Al grains ≤ 60 µm for the refined alloys compared with the unrefined alloy. Additionally, the growth of α-Al slurry globules was greater for the unrefined alloy compared with the refined alloy during solidification in the die-cavity. A more homogeneous and finer microstructure was observed near the surface in the grain-refined castings compared with the unrefined castings. Evidence of significant liquid penetration was identified in some α-Al globules, indicating that disintegration of α-Al globules may occur during the Rheometal™ casting process.

     

Experimental Investigation of Wire Electrical Discharge Machining of NdFeB Permanent Magnets with an RC-Type Machine

This paper focuses on wire electrical discharge machining (WEDM) of devices made from commercially available sintered neodymium-iron-boron (NdFeB) rare-earth magnets that have been magnetized before machining. We conduct an experimental study to quantify the effects of the voltage and capacitance of an RC-type WEDM machine, as well as the magnet polarity, on slicing rate, mean kerf, and variation in kerf. We find that voltage and capacitance affect slicing rate, that voltage affects mean kerf, that no parameters tested affect the variation in kerf, and that the polarity of the magnet being machined does not affect the machining process. Linear regression is used to fit simple predictive models to the data with good agreement. Further analysis is performed to characterize the loss in permanent magnetization on the surface of the magnet due to heating during the machining process, and it is found that the outer layer of approximately 35 μm in depth is demagnetized when using the highest voltage and capacitance values tested.     

A diagnosis method of wear and tool life for an endmill by ultrasonic detection

This study used ultrasonic scanning to investigate the contact between end-mill cutters and workpieces. This method is novel for endmills and has not been applied before. Contact shapes were disclosed and a comparison of contact images and areas was made from the experimental results. It is not a dynamic or online monitoring during the cutter machining process. Instead, it is only a static measurement because the objective is to provide the information for users to know the area size of a worn end-mill cutter. The 2D maps show an apparent change not only in area sizes but also in contact shapes for the used endmills. The 3D maps disclose the information for which region is in light or heavy contact.