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In order to study the air gap magnetic field distribution and torque of axial-flux solid magnetic couplers with 9 pairs of permanent magnets, a layer model is firstly introduced, which divides the couplers into conductive and non-conductive areas. The two-dimensional magnetic scalar potential method is derived to solve the magnetic field strength in conductive areas and the magnetic scalar potential in non-conductive areas. Carter coefficient is introduced to correct the 3D end effects, and the formula of air gap flux density and torque is derived. Then， the distribution of 3D air gap magnetic field, eddy current and the influence of different working parameters on the characteristics of the torque are obtained by the finite element simulation software. Finally, a measure system of three-dimensional magnetic field and the magnetic drive experimental platform are built to measure the 3D air gap magnetic field and the torque. The experimental results are in good agreement with the results of theoretical calculation and the simulation analysis, which shows that the formula of the air gap flux density and the torque have high accuracy and can be used as a reference for further research on the transmission characteristics of eddy-current magnetic couplers.

Aiming at the speed regulation characteristics of slotted-type eddy-current couplers, the expression of the induced magnetic field generated by the induced eddy current is derived by using Ampère's law and the induced magnetic field is introduced into the equivalent magnetic circuit model. Then, the calculation formula of electromagnetic torque is derived in combination with Kirchhoff's law. The electromagnetic torque formula is combined with the expression of constant torque load and quadratic rate load respectively, and the theoretical formula of the speed regulation relationship under corresponding load conditions is obtained. The 3D finite element simulation and experiment are used to verify the proposed theoretical model of speed regulation. It is found that the proposed theoretical model has good accuracy in the case of small air gap length.

In order to study the transmission performance of slotted-type eddy-current couplers with radial misalignment, based on the theory of the equivalent magnetic charge theory, the copper which cuts the magnetic field line in motion is equivalent to permanent magnet. Combining with Coulomb's law, a calculation model of output torque is established in this study. The analysis of magnetic flux density, copper loss and output torque of couplers are all simulated by finite element software, and the maximum allowable value of radial misalignment is obtained. The results show that with the increase of radial misalignment, the induced magnetic field decreases during operation, which results in the increase of the magnetic flux density, the decrease of the copper loss and the torque, and the fluctuations of the copper loss and the output torque changing with time become more and more obvious. When the radial misalignment is less than 6 mm, the torque generated by the couplers can almost be remained accurately and the fluctuation of the torque is relatively stable.

In order to solve the problem of calculating the air gap magnetic field and torque of slotted-type magnetic couplers, a subdomain analysis model is introduced. The magnetic couplers are divided into five regions along the axis, the boundary equations are established at the interfaces of each region. According to the alternating arrangement characteristics of yoke teeth and the conductor and the vector magnetic potential formulas in yoke teeth and the copper conductor disk are deduced respectively. Due to the end effect, Schwarz-Christoffel mapping is used to modify the coefficient of the flux density at the end face of the cogging. On the basis of obtaining the vector magnetic potential of the yoke iron and conductor respectively, the formulas of the air gap magnetic field and electromagnetic torque are deduced. The structure parameters of the slotted-type magnetic couplers are substituted into the theoretical model to calculate the axial air-gap magnetic field distribution and mechanical characteristic curves. By comparing the results with those obtained by finite element simulation, the accuracy of the theoretical model is verified and the cause of the error is analyzed.

Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources. The Digital Twin technology becomes a promising tool in optimizing the processes of wildfire prevention, monitoring, disaster response, and post-fire recovery. This review examines the potential utility of Digital Twin in wildfire management and aims to inspire further exploration and experimentation by researchers and practitioners in the fields of environment, forestry, fire ecology, and firefighting services. By creating virtual replicas of wildfire in the physical world, a Digital Twin platform facilitates data integration from multiple sources, such as remote sensing, weather forecasting, and ground-based sensors, providing a holistic view of emergency response and decision-making. Furthermore, Digital Twin can support simulation-based training and scenario testing for prescribed fire planning and firefighting to improve preparedness and response to evacuation and rescue. Successful applications of Digital Twin in wildfire management require horizontal collaboration among researchers, practitioners, and stakeholders, as well as enhanced resource sharing and data exchange. This review seeks a deeper understanding of future wildland fire management from a technological perspective and inspiration of future research and implementation. Further research should focus on refining and validating Digital Twin models and the integration into existing fire management operations, and then demonstrating them in real wildland fires. [ABSTRACT FROM AUTHOR]

BACKGROUND: As a novel type of extracellular polysaccharide produced by Sphingomonas sp., welan gum has been widely applied in various fields because of its excellent properties. The study has improved the fermentation process. Results: The initial sucrose concentration, temperature and stirring speed were set to 20 g L−1, 33 °C and 400 rpm, respectively, and 13.3 g L−1 sucrose was added at 24, 40 and 56 h. The temperature and stirring speed were then set at 28 °C and 600 rpm from 24 to 48 h and 28 °C and 600 rpm from 48 to 72 h, respectively. As a result, welan gum production, dry cell weight, sucrose conversion rate and viscosity were correspondingly increased to 38.60 g L−1, 5.47 g L−1, 0.64 g g−1 and 3779 mPa·s, respectively. In addition, the mechanism by which fermentation strategy promotes welan gum synthesis was investigated by transcriptome analysis. CONCLUSION: Improving respiration and ATP supply, reducing unnecessary protein synthesis, and alleviating competition between cell growth and welan gum synthesis contribute to promoting the fermentation performance of Sphingomonas sp., thus providing a practical strategy for efficient welan gum production. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]