Optimization of the Guiding Stability of a Horizontal Axis HTS ZFC Radial Levitation Bearing

This document presents a study on the optimization of the 3D geometry of a horizontal axis radial levitation bearing with zero-field cooled (ZFC) high-temperature superconductor (HTS) bulks in the stator, and radially magnetized permanent magnet (PM) rings in the rotor. The optimization of component dimensions and spacing to minimize the volume or cost concerning only the maximization of the levitation force was previously studied. The guidance force and guiding stability depend on the spacing between PM rings in the rotor and between the rings of HTS bulks in the stator. This new optimization study aims to find the optimum spacing that maximize the guidance force with given HTS bulk and PM ring dimensions while maintaining the minimum required levitation force. Decisions are taken using the non-dominated sorting genetic algorithm (NSGA-II) over 3D finite element analysis (FEA). A simplified electromagnetic model of equivalent relative permeability is used on 3D FEA to reduce numerical processing and optimization time. Experimental prototypes were built to measure magnetic forces and validate appropriate values of equivalent magnetic permeability. An analysis of stable and unstable geometry domains depending on the spacing between rings of HTS bulks and PM rings is also done for two HTS bulk sizes.

DILEMMA AND PATH SELECTION OF COLLEGE SPORTS RESOURCES INTO THE PUBLIC SERVICE SYSTEM OF NATIONAL FITNESS IN THE NEW ERA

ABSTRACT With the improvement of people's yearning for a healthy and beautiful life, national fitness has become a hot word in academic circles. Combining Data Envelopment Analysis (DEA) and the Tobit technology, this paper constructs the evaluation model of college sports resource efficiency based on the DEA Tobit model. Based on the establishment of the input-output index system of college sports resources, the model achieves the effect of accurate analysis on the allocation efficiency of university sports resources. Taking 10 universities in a city as experimental objects, the model is verified. The verification shows that the three efficiency indexes of STU University and IPE University in group M are all 1, which shows that the resource allocation is more reasonable; the comprehensive efficiency of Ju university is low, and the sports resources investment is excessive; in group n, except for the EU University, the efficiency of other colleges and universities is lower than the pass line. It can be concluded that there are problems such as excessive input of sports resources and low output rate in Colleges and universities of a city. Therefore, colleges and universities in a city should make full use of the existing resources, enhance their social sports guidance force, while improving the publicity of national fitness. This study has high reference significance for the path selection of national fitness integration in Colleges and Universities.

Deep Learning-Based Haptic Guidance for Surgical Skills Transfer

Having a trusted and useful system that helps to diminish the risk of medical errors and facilitate the improvement of quality in the medical education is indispensable. Thousands of surgical errors are occurred annually with high adverse event rate, despite inordinate number of devised patients safety initiatives. Inadvertently or otherwise, surgeons play a critical role in the aforementioned errors. Training surgeons is one of the most crucial and delicate parts of medical education and needs more attention due to its practical intrinsic. In contrast to engineering, dealing with mortal alive creatures provides a minuscule chance of trial and error for trainees. Training in operative rooms, on the other hand, is extremely expensive in terms of not only equipment but also hiring professional trainers. In addition, the COVID-19 pandemic has caused to establish initiatives such as social distancing in order to mitigate the rate of outbreak. This leads surgeons to postpone some non-urgent surgeries or operate with restrictions in terms of safety. Subsequently, educational systems are affected by the limitations due to the pandemic. Skill transfer systems in cooperation with a virtual training environment is thought as a solution to address aforesaid issues. This enables not only novice surgeons to enrich their proficiency but also helps expert surgeons to be supervised during the operation. This paper focuses on devising a solution based on deep leaning algorithms to model the behavior of experts during the operation. In other words, the proposed solution is a skill transfer method that learns professional demonstrations using different effective factors from the body of experts. The trained model then provides a real-time haptic guidance signal for either instructing trainees or supervising expert surgeons. A simulation is utilized to emulate an operating room for femur drilling surgery, which is a common invasive treatment for osteoporosis. This helps us with both collecting the essential data and assessing the obtained models. Experimental results show that the proposed method is capable of emitting guidance force haptic signal with an acceptable error rate.

Multiphysics analysis of a hybrid suspension system for middle-low-speed maglev trains

The suspension force − a critical factor in the operation of middle-low-speed maglev trains − is provided by electromagnets. However, the eddy current effect produced by the relative motion between electromagnets and the steel track causes a reduction of the suspension force, especially under high speed. A novel type of permanent-electro-magnetic suspension system is proposed to improve performance by considering the variation of material characteristics with temperature. A 3D dynamic finite element model of this hybrid system − accounting for the influence of temperature − has been created to study the variation of magnetic flux distribution, suspension force and guiding force under different operational speeds of the train, in comparison with the electromagnetic version. Verified by simulations, the hybrid system has superior performance offering a powerful suspension force and a reliable guidance force even at high speeds of the train.