Theoretical design and dynamic simulation of new mining paths of tracked miner on deep seafloor

With comprehensive considerations of the operational safety and collection efficiency for the tracked miner collecting the seafloor poly-metallic nodules, two new improved mining paths for the miner on the deep seafloor were proposed. Compared to the conventional mining path, the design principles and superiorities of the two new paths are that the miner turning with relative long radius should avoid large sinkage and high slip, so as to ensure its operational safety, while the space between its straight-line trajectories before and after the turning is optimum, which is designed as the total width of the miner, and collect nodules as more as possible, so as to ensure its collection efficiency. To realize the new mining paths, theoretical designs and quantitative calculations were carried out to determine the exact positions for the speed controls of the miner during its whole operation process. With the new dynamic model of the miner, and through regulations of the speeds of the left and right tracks of the miner on the exact motion positions according to the theoretical calculations, the two new improved mining paths for the miner on the seafloor were successfully simulated, thus the turning radius of the miner in the simulation is about 21.8 m, while the distance between the straight-line trajectories before and after the turning is about 5.2 m. The dynamic simulation results preliminarily prove the feasibility of these two new mining paths, and further can provide important theoretical guidance and useful technical reference for the practical tracked miner operation and control on the seafloor.

Making Use of the Eddy Currents Effect in the Examination of the Tribological Characteristics of Strip Rolling Mill Rolls

The key element in the proper performance of a rolling mill is the careful planning of the rolls operational conditions, since this factor constitutes the restricting element in the manufacturing process. In the article, a collection of operation and research steel strips hot-rolling mill information was presented, which was processed based on the advanced computer programmes for rolls grinders. The research outcomes were produced, presenting the application of eddy currents to detect materials flaws in metallurgical mill rolls.

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Clinical study on Tuina plus physical agents for lateral collateral ligament injury of ankle in gymnasts

Objective To compare the efficacy of Tuina(Chinese therapeutic massage)plus physical agents and physical agents alone for lateral collateral ligament injury of ankle in gymnasts,and to explore the feasibility of Tuina for injury intervention in competitive athletes.Methods A total of 64 gymnasts with types Ⅰ-Ⅱ lateral collateral ligament injury of ankle were selected and divided into a control group and an observation group according to a full analysis set based on the intention-to-treat principle,with 32 cases in each group.Patients in the control group received ultrasound and microwave treatment,while those in the observation group received additional Tuina manipulations.The efficacy was evaluated by total effective rate,visual analog scale(VAS)score,and American Orthopedic Foot and Ankle Society ankle-hindfoot scale(AOFAS-AHS)score.Results The total effective rate was 96.9% in the observation group and 90.6% in the control group.There was no statistical difference in the total effective rate between the two groups(P>0.05).The markedly effective rate was 75.0% in the observation group and 46.9% in the control group.The markedly effective rate in the observation group was higher than that in the control group(P<0.05).After treatment,the VAS scores of both groups showed a downward trend,and there were statistical differences between different treatment time points in the same group(P<0.05).After one and three months of treatment,the VAS scores of the observation group were lower than those of the control group(P<0.05).There were statistical differences in the AOFAS-AHS score before and after treatment within the same group(P<0.05).After one month of treatment,there was no statistical difference in the AOFAS-AHS score between the two groups(P>0.05).After three months of treatment,the AOFAS-AHS score in the observation group was higher than that in the control group,indicating statistical significance(P<0.05).There was an interaction between time and group(P<0.05).Conclusion Tuina plus physical agents can improve the symptoms of lateral collateral ligament injury of ankle in gymnasts.This combined treatment is superior to physical agents alone in relieving pain and improving joint functions.Therefore,Tuina plus physical agents can be used as a treatment for lateral collateral ligament injury of ankle in gymnasts.

Selective excitation of resonances in gammadion metamaterials for terahertz wave manipulation

A gammadion terahertz(THz) metamaterial embedded with a pair of splits is experimentally investigated. By introducing the pair of splits at different arms, the transmitted amplitude at the resonance frequency can be manipulated from 61% to 24%. Broadband static resonance tunability from 1.11 to 1.51 THz is also demonstrated via varying the relative split positions at certain arms. The amplitude change and static resonance tunability are attributed to the introduced split pairs, which enable selective excitation of different resonance modes in the gammadion metamaterials. This work promises a new approach to design THz functional devices.