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Ohmic heating has become one of the main factors restricting their efficiency and longevity of the synchronous induction coilgun (SICG) operating in a complex electromagnetic environment. Therefore, further exploration on the temperature spatial–temporal distribution characteristics of the SICG is of great practical significance to ensure its reliable and efficient operation. The single-stage SICG is taken as the research object to simplify the solving process. First, the effectiveness and accuracy of the numerical simulation models in terms of kinetic and thermodynamic properties are compared and verified. Then, the influence of different structural parameters on temperature rise and acceleration is investigated in detail. The conclusions can not only provide theoretical reference for the long-term service of the SICG but also guide the related research of continuous emission.

Based on long air gap discharge test data and lightning return stroke observation data, an improved electrogeometric model (EGM) considering terrain conditions is established and verified to analyze the lightning shielding performance of UHV transmission lines. The striking distance formula is modified as rs = 0.13 (I2 + 40I)0.814. In this paper, the lightning shielding failure rate of three-phase conductors of EHV and UHV transmission lines calculated by the improved EGM model is consistent with the lightning observation data of actual transmission lines in Japan and the scaled lightning discharge simulation experimental results of UHV transmission lines in plains and mountainous areas of China, which verifies the applicability of the improved EGM model to evaluate the lightning shielding performance of large-scale UHV transmission lines. The improved EGM model is applied to evaluate the influence of tower type and slope steepness on the shielding failure tripping rate of UHV transmission lines. The shielding failure tripping rate of the SZ322 tower is higher than that of the SZT1 tower, and the shielding failure tripping rate of UHV transmission lines is greatly affected by slope gradient and increases with the increase of slope gradient.

Synchronous induction coilgun (SICG) has received tremendous attention in the military and civilian fields, which can be attributed to their inherent excellent noncontact linear propulsion characteristics. Theoretically, the ferromagnetic projectile can be launched at hyper-speed by multistage coil relay propulsion. However, the consensus of the SICG on low-speed and large-load propulsion has made its medium-high speed launch a controversial topic, hampered in part by lack of in-depth exploration of simulation model. Based on the previous work, this article focuses on the matching characteristics of slip and turns in order to obtain more reasonable parameter design strategy for the high-speed SICG. First, the numerical simulation model of multistage SICG is constructed on the premise of idealized assumptions to describe the energy conversion process. Then, the concept of slip is explained and the calculation formulas of slip and turns are derived, respectively. Finally, the operating characteristics of the two matching strategies of slip and turns are analyzed. The conclusions obtained by theoretical derivation and simulation comparison can provide reference for the design of medium-high speed SICG.

As natural lightning strikes on a transmission tower, lightning current will flow along grounding lines into the adjacent tower grounding grid. As lightning current is dispersed from the tower grounding grid into the soil, a lightning overvoltage may be produced on adjacent pipelines. In this paper, the lightning current shunt characteristics in multi-tower scenarios are calculated by simulation method under different soil resistivity conditions. Then, based on the lightning current shunt characteristics, the current dispersion process among multi-tower grounding grids and the pipeline is analyzed with different soil resistivities, gap distances, and lightning current amplitudes. Finally, the protective effect of “drain wire” and “forced commutation” on pipeline overvoltage are compared. Simulation results showed that with increasing soil resistivity, tower grounding resistance was increased and tower shunt coefficient decreased. Considering lightning current through the multi-tower grounding grids, pipeline overvoltage is much larger than that of a single tower. Pipeline overvoltage is increased with soil resistivity and lightning current amplitude, while it is decreased with “pipeline-line” distance. Both “drain wire” method and “forced commutation” method can effectively reduce pipeline potential.

COVID-19 pandemic response measures have brought unprecedented challenges to the UN 2030 Agenda for the Sustainable Development Goals (SDGs) and a quantitative, multi-dimensional assessment of the impacts of these response measures on SDG progress is required. Here, we use an adaptive multi-regional input-output model to quantitatively assess the impact of pandemic responses on global and national SDG progress and show that COVID-19 pandemic responses (i.e., movement restrictions, fiscal stimuli, and trade restrictions) have reduced overall progress towards the SDGs by 7.2%, with socio-economic sustainability scores declining by 23.9% while environmental sustainability scores improved by 11.6% compared with the BAU trend. Developing countries suffered slightly greater reductions in overall sustainability (7.8%) than developed countries (6.4%). Under all post-pandemic futures, pandemic responses impeded overall progress towards the 2030 Agenda and worsened inequality in sustainable development between countries, particularly for socioeconomic targets. A post-pandemic strategy toward the UN 2030 Agenda requires sustainable pandemic responses, which not only address inequality among countries but also lessen the trade-offs between SDGs.

The armature structure is the key to the electromagnetic orbit emission. In the initial stage of launch, a good initial contact between the armature and the orbit can effectively avoid transition. First, an L16(54) orthogonal table was established in this article to obtain 16 groups of numerical simulation schemes, and the range and variance analyses of numerical results were carried out. The results show that the main factors affecting the peak contact pressure and stress are shoulder thickness and interference. The secondary factors are the tail length, tail tip thickness, and leading foot thickness; second, a machine learning method based on a multiple linear regression normal equation method is adopted to predict its contact state. The prediction error can be controlled within 10%; finally, parametric scanning is carried out on the basis of machine learning and a new method of armature structure optimization is proposed to improve the initial contact state. The optimized armature can greatly reduce its stress peak. This research provides a new method for the armature structure optimization design.

Superconducting inductive pulsed power supplies, which are used in electromagnetic rail-gun (EMRG) application, have attracted a lot of attention during recent years. In this paper, a repetitive inductive pulsed power supply circuit based on a high-temperature superconducting transformer is proposed to drive EMRG. The circuit is capable to recover the remaining energy of the system before the end of an electromagnetic launch. This is beneficial to eliminate the muzzle arc of EMRG and improve the energy transfer efficiency. In order to prove the feasibility, a 3-m-long simple EMRG model was used for simulation. The driving process of the circuit was analyzed and the output characteristics were studied. The simulation results show that the repetitive inductive pulse forming circuit is suitable for driving EMRG. Reasonable selection of circuit parameters can improve the launching performance of the system.

Superconducting inductive pulsed power supplies have attracted a lot of attention due to its lower electrical loss and higher energy storage density than traditional inductors. To effectively improve charging rate and output continuous current pulses, a repetitive inductive pulsed power supply circuit topology based on high-temperature superconducting (HTS) pulsed power transformer was proposed and simulated in our previous studies. This paper aims to further study the feasibility of the repetitive inductive pulsed power supply circuit topology through experiments. A small air-core HTS pulsed power transformer and a bridge-type capacitor switching circuit were used to build the experimental platform. The experimental results show that the bridge-type capacitor switching circuit can shorten the charging time of each new cycle and the repetitive inductive pulsed power supply circuit is feasible for continuous current pulse output.

Long-term storage of aerobic granular sludge (AGS) may lead to granule inactivation and disintegration. Granule recovery in both structure and activity is important for scale-up and stability of AGS, but information about the structure recovery of stored AGS is limited. In addition, whether short-term exogenous N-acyl-homoserine lactones (AHLs) regulations could accelerate the granule recovery and sustain positive effects on AGS is unknown. Herein, the recovery of 33-month stored AGS was performed in three reactors for 38 days (phase I) at different exogenous AHLs concentrations (0, 50 and 500 nM of AHL-mixtures in R0, R1 and R2, respectively) and for an extended 45 days without exogenous AHLs (phase II). Results demonstrated successful recovery of disintegrated AGS in all reactors, although it was relatively time-consuming in R0. The treatment performance was similar among the reactors and steady-state removal of COD (90%) and NH4+-N (94%) could be recovered within 7 and 21 days, respectively. However, exogenous AHLs regulation (especially in R1) obviously accelerated bioactivity recovery of heterotrophs and nitrifiers and improved granule characteristics, including biomass, density, hydrophobicity and extracellular polymeric substance (EPS). During phase II, sustainable positive effects remained in R1, but granule characteristics deteriorated in R2. The abundance of functional genera Thauera, Nitrosomonas and Candidatus_Nitrotoga, contributed to the rapid recovery and helped maintain the structure and activity of AGS. The predictive functional profiling of bacterial communities also demonstrated sustainably higher activities of metabolism, growth and signal sensing under exogenous AHLs regulation at an appropriate content.