Effect of the protection layer formed by cross-linked gelatin on the stability and performance of glucose and oxygen fuel cells

Fuel cell is an electrochemical device, which can directly convert the chemical energy of fuel into electric energy, without heat process, not limited by Carnot cycle, high energy conversion efficiency, no noise and pollution.

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Analytical Modeling and Design of Novel Conical Halbach Permanent Magnet Couplings for Underwater Propulsion

Journal of Marine Science and Engineering ◽

10.3390/jmse9030290 ◽

2021 ◽

Vol 9 (3) ◽

pp. 290

Author(s):

Yukai Li ◽

Yuli Hu ◽

Youguang Guo ◽

Baowei Song ◽

Zhaoyong Mao

Keyword(s):

Permanent Magnet ◽

Analytical Calculation ◽

Underwater Propulsion ◽

Conical Structure ◽

Torque Analysis ◽

Dynamic Seal ◽

And Performance ◽

The Stability ◽

Propulsion Unit ◽

Force Calculation

Permanent magnet couplings can convert a dynamic seal into a static seal, thereby greatly improving the stability of the underwater propulsion unit. In order to make full use of the tail space and improve the transmitted torque capability, a conical Halbach permanent magnet coupling (C-HPMC) is proposed in this paper. The C-HPMC combines multiple cylindrical HPMCs with different sizes into an approximately conical structure. Compared with the conical permanent magnet couplings in our previous work, the novel C-HPMC has better torque performance and is easy to process. The analytical calculation method of transmitted torque of C-HPMC is proposed on the basis of torque calculation of the three common types of HPMCs. The accuracy of the torque calculation of the three HPMCs is verified, and the torque performance of the three HPMCSs of different sizes is compared and discussed. The “optimal type selection” method is proposed and applied in the design of C-HPMC. Finally, on the basis of torque analysis calculation and axial force calculation, a complete flowchart of the design and performance analysis of C-HPMC is described.

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Adaptive attitude-tracking control of spacecraft considering on-orbit refuelling

Transactions of the Institute of Measurement and Control ◽

10.1177/0142331220973132 ◽

2020 ◽

pp. 014233122097313

Author(s):

Yiqi Xu

Keyword(s):

Tracking Control ◽

Closed Loop ◽

Closed Loop System ◽

Tracking Errors ◽

Attitude Tracking ◽

Control Scheme ◽

Inertia Model ◽

And Performance ◽

Attitude Tracking Control ◽

The Stability

This paper studies the attitude-tracking control problem of spacecraft considering on-orbit refuelling. A time-varying inertia model is developed for spacecraft on-orbit refuelling, which actually includes two processes: fuel in the transfer pipe and fuel in the tank. Based upon the inertia model, an adaptive attitude-tracking controller is derived to guarantee the stability of the resulted closed-loop system, as well as asymptotic convergence of the attitude-tracking errors, despite performing refuelling operations. Finally, numerical simulations illustrate the effectiveness and performance of the proposed control scheme.

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Nondestructive Test on Typical Roadway Supports of a Mine via Drilling Core and Ground Penetrating Radar

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.368-373.2411 ◽

2011 ◽

Vol 368-373 ◽

pp. 2411-2416

Author(s):

Jian Ping Han ◽

Hai Peng Liu

Keyword(s):

Ground Penetrating Radar ◽

Geological Structure ◽

Surrounding Rock ◽

Potential Threat ◽

Real Performance ◽

Design Requirements ◽

And Performance ◽

The Stability ◽

Ground Penetrating ◽

Drilling Core

Temporary or permanent supports are necessary in underground construction for maintaining the stability and limiting the damage of surrounding rock. Due to the uncertainty of geological structure, the specificity of the underground environment as well as other factors, the quality and performance of supporting structure are often difficult to satisfy the design requirements, which not only seriously affects the normal construction and operation of mines but also has the potential threat to the safety of underground production. In order to investigate the influence of the unfavorable geologic environment on supporting concrete and evaluate the real performance of roadway supports of a mine, 17 typical projects were chosen and the strength of supporting concrete was detected by nondestructive drilling core method. The result shows that the strength is widely less than the design value. Furthermore, 4 projects of them were investigated by the ground penetrating radar (GPR) in order to evaluate the feasibility of GPR in the performance investigation of the roadway supports of a mine. The results indicate that ground penetrating radar is capable of measuring the thickness of the support, the distribution of rebars and the defects of the surrounding rock.

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