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•Synthetic community diversity increased under simulated space environments.•The number of Bacilliincreased significantly under space environmental stress.•The resistance of penicillin antibiotics in synthetic communities increased under LDIR.•Antibiotic biosynthesis increased in synthetic community under space environmental stress.

In this paper, a nonlinear dynamics equation for a micro electromagnetic harmonic drive system is proposed considering nonlinearity caused by the molecule force applied to the flexible ring. Using the equations, the nonlinear resonant frequencies and the amplitude frequency characteristics of the drive system are investigated. Effects of the molecule force nonlinearity on the resonant frequencies and the amplitude-frequency characteristics and their changes along with system parameters are analyzed. Results show that the nonlinear effect of van der Waals forces on system vibration should be considered when the coil current and the radius of the flexible wheel are large, the thickness of the flexible wheel or the gap between the flexible wheel and the stator is small. The jump vibration zone of the flexible wheel reduces significantly with increasing the exciting current in the coil, the length of the flexible wheel, and the nonlinear parameter, or decreasing the thickness of the flexible wheel.

The crack initiation stage is crucial to the overall fatigue behavior of the carbide-free bainitic steels. Through S–N curve testing and fracture observation, it is demonstrated that internal crack initiation is the dominant mode during high cycle fatigue. The crack initiation region exhibits a tilted micro-facet feature, which is along the direction of the maximum shear stress. Through fine characterization of crack initiation region, we proposed the crack initiation mechanism of dislocation dipoles pileup at prior-austenite grain boundaries in slip bands. Finally, the lifetime of the crack initiation stage was estimated from the deformation energy stored by dislocations pileup. It is beneficial for life prediction of the whole fatigue process for CFB steels in the future.

Comprehending urban form and function is crucial for effective urban planning and redevelopment. However, delineating urban functional zones and understanding the diverse activities within a city poses challenges. To address this, our study proposes a comprehensive analysis framework utilising point-of-interest (POI) data to identify and characterise urban functional zones and associated amenities. Leveraging geocoded user-generated content enables an effective capture of the spatial structure of human activities. We applied our framework in case studies in two Singapore locations, demonstrating its effectiveness in identifying urban functional zone shapes and examining associated amenities. The findings reveal a spatial configuration of amenities across the urban area, highlighting a diversity often differing from planned land-uses. This underscores the complex and non-uniform nature of the urban living experience, as observed variations in mixed uses challenge the homogeneity of intended land-use types. Our study and analysis framework provide a foundation for further investigations, including exploring travel behaviour patterns and assessing the vibrancy and vitality of urban areas.

ABSTRACTLight intensity and nitrogen concentration in nutrient solutions are two main factors affecting the growth and nutritional quality of lettuce(Lactuca sativaL.). This study investigated the method of regulating vegetable cultivation through the interactive control of the light environment and solution ratio. A quadratic regression orthogonal model was developed to understand the role of light intensity (43 to 237 µmol m−2s−1) and nitrogen concentration (4.3 to 23.7 mmol L−1) in lettuce growth. Dry weight, vitamin C, and nitrate contents were measured and modelled to understand the coupling effect of light intensity and nitrogen concentration on lettuce. The optimised conditions for lettuce growth were 237 µmol m−2 s−1of light intensity and 9.2 mmol L−1of nitrogen concentration, and these conditions were predicted to produce lettuce with an average dry biomass of 3.9 g plant−1, 149.9 µg g−1of Vitamin C, and 212.1 µg g−1of nitrate content based on their respective weighting factors (0.50, 0.25, and 0.25). The lettuce yield and quality were verified using the modelled optimised growth conditions and the lettuce grown was indeed more nutritional compared to the commercially available lettuce. The findings are important for mass production of lettuce in plant factories and greenhouses.

Since the industrial revolution, anthropogenic activities, such as fossil fuel use and deforestation, have caused a dramatic increase in the atmospheric CO2concentration. To understand how the growth and development in cereal crops may respond to elevated CO2, it is necessary to determine if the leaves of crops grown in a closed artificial ecosystem have a fully developed photosynthetic apparatus and whether or not photosynthesis in these leaves is more responsive to an elevated CO2concentration. To address this issue, we evaluated the response of the photosynthetic characteristics, antioxidant capacity, and water use efficiency of wheat (Triticum aestivumL.) under four CO2concentrations (500, 1000, 3000, and 5000 ppm) for 3 d in Lunar Palace‐1, which is the first bioregenerative life support system developed in China. The results showed that wheat cultivated at 1000 ppm from vegetative growth to maturity was characterized by more appropriate relative water content, membrane stability index, photosynthetic rate, chlorophyll concentration, and antioxidant capacity, which was more beneficial to growth and development in a closed artificial environment. There were significant effects with increased CO2concentration on the effective quantum yield of PSII and photosynthetic electron transport of wheat plants. Furthermore, elevated CO2controlled the transpiration rate, which enhanced water use efficiency. During ripening, wheat aging may be accelerated by elevated CO2, which promotes grain growth and maturing.

•Analyzing research of bioregenerative life support system (BLSS) around the world, this article summarizes the theoretical/technological system framework and development path of BLSS, and proposes evaluation indices and the “three-stage” development path for extraterrestrial BLSS.•To guide the establishment of Earth-based and extraterrestrial BLSS, this article proposes “three key conditions of BLSS gas balance”, which is the key to the stability of BLSS.