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Since Autonomous Underwater Vehicles (AUVs) generally have the limited sensing range and endurance, dynamic real-time trajectory planning is essential in the complex marine environment. In this paper, we propose a dynamic trajectory planning method for AUVs in a hierarchical and receding horizon way. Hierarchically, trajectory optimizations are conducted sequentially to maintain the high computational efficiency. Within each planning horizon, a safe global path is first searched for and the path is then optimized over a short horizon within the limited sensing range. Particularly, for the global path search, the hybrid A* algorithm is employed to find a collision-free path while considering the kinematic constraints of the AUV. To enhance the smoothness and safety of the path, a nonlinear optimization problem is further solved to refine the path over the short horizon. To further guarantee the feasibility of the planned path for the AUV, the inverse dynamics in the virtual domain (IDVD) method is proposed to perform a joint spatio-temporal optimization to obtain the feasible AUV velocity and acceleration trajectories. To validate the proposed trajectory planning method, both simulations and experiments with a newly developed flat disk-shaped AUV, Stingray II, are conducted. It is demonstrated that the proposed method is capable of efficient online trajectory planning in unknown and complex environments for AUVs. • A receding horizon and hierarchical planning strategy is proposed for AUVs. • Both path optimality and computational efficiency are achieved. • Pool experiments are conducted with a real AUV to demonstrate the effectiveness. [ABSTRACT FROM AUTHOR]

• Soil carbon pool is closely correlated with tobacco aroma. • Improvement of the soil carbon environment may improve tobacco aroma. • Soil microbial community are linked to tobacco aroma. Soil carbon pool, the largest carbon pool in any terrestrial ecosystems, has been disrupted owing to high rates of fertilization and intensive crop rotation. Reduction of soil carbon caused decreases of tobacco quality. Firstly, the correlations between soil types (purple soil and paddy soil from the tobacco region in southern China) and tobacco aroma compounds were analyzed in this research. It was showed that the soil carbon pool is closely correlated with tobacco aroma. Secondly, effect of the soil carbon content on soil microorganisms were analyzed. The results indicated that improvement of the soil carbon increased the tobacco aroma and the abundance of Lactobacillales and Oceanospirillales. The present study revealed the correlations between the soil carbon, microbial community structure and tobacco quality, demonstrating the importance of improving the soil carbon for increasing tobacco quality. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hyperspectrum was applied to analyze the nicotine content of tobacco. [•] Identified the central bands and their optimum combination for nicotine content. [•] Established new spectral indices to monitor tobacco nicotine status. [•] The BP neural network based on the new spectral indices was more accurate and stable. [Copyright &y& Elsevier]

Highlights: [•] Hyperspectra was applied to analyze the LNC of tobacco using two-year data. [•] Identified the central bands sensitive to tobacco LNC and their optimum combination. [•] Established new spectral indices thus greatly facilitate monitoring of tobacco LNC. [•] The BP neural network based on the new spectral indices was more accurate and stable. [ABSTRACT FROM AUTHOR]

Abstract: Alkaline fuel cells suggest solution for the problems of low methanol oxidation kinetics and methanol crossover, which are limiting the development of direct methanol fuel cells. In this work, a novel anion exchange membrane, quaternized poly(aryl ether oxadiazole), was prepared through polycondensation, grafting and quaternization. The ionic conductivity of as-synthesized anion exchange membrane can reach up to 2.79 × 10−2 S/cm at 70 °C. The physical and chemical stability of the anion exchange membranes could also meet the requirement for alkaline direct methanol fuel cells. [Copyright &y& Elsevier]

• MEG with suitable layer spacing were prepared. • MEG facilitates the intercalation/de-intercalation of the large size anions. • Hierarchical MoS 2 @C sphere provides void spaces for buffering volume expansion. • MEG-2//MoS 2 @C-800 DIB exhibits a high energy density of 286.97 Wh kg−1. Dual-ion batteries (DIBs) have received tremendous attention due to the high energy density provided by the high operating voltage and the low cost as a result of the abundance of active materials. However, the overall performance of known DIBs is far below expectations. In particular, graphite cathode with fast charge/discharge abilities and high-capacity anode materials still need to be further explored. Herein, a sophisticated overall DIB design is proposed by employing a mildly expanded graphite (MEG) as the cathode and a hierarchical carbon coated MoS 2 sphere (MoS 2 @C) as the anode. MEG with suitable layer spacing facilitates the intercalation/de-intercalation of the large size anions, greatly enhancing the reaction kinetics. The distinctive structural design of MoS 2 @C not only shortens the Li+ diffusion channel, but also improves the electrical conductivity and significantly relieves the volume expansion during repeated cycles. The as-built MEG-2//MoS 2 @C-800 full DIB demonstrates better specific capacity and higher discharge medium voltage (77.29 mAh g −1 at 1 C and discharge medium voltage remains above 3.5 V after 200 cycles). More impressively, this DIB can deliver an outstanding energy density of 286.97 Wh kg−1 at the power density of 775.59 W kg−1, which is superior to other energy storage devices including Ni-Cd batteries, lead-acid batteries, electrochemical capacitors, Li-ion batteries and most previously reported DIBs. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Crosslinked organic–inorganic hybrid membranes are prepared from hydroxyl-functionalized sulfonated poly(ether ether ketone) (SPEEK) and various amounts of silica with the aims to improve dimensional stability and methanol resistance. The partially hydroxyl-functionalized SPEEK is prepared by the reduction of some benzophenone moieties of SPEEK into the corresponding benzhydrol moieties which is then reacted with (3-isocyanatopropyl)triethoxysilane (ICPTES) to get a side chained polymer bearing triethoxysilyl groups. These groups are subsequently co-hydrolyzed with tetraethoxysilane (TEOS) and allow the membrane to form a crosslinked network via a sol–gel process. The obtained hybrid membranes with covalent bonds between organic and inorganic phases exhibit much lower methanol swelling ratio and water uptake. With the increase of silica content, the methanol permeability coefficient of the hybrid membranes decreases at first and then increased. At silica content of about 6wt.%, the methanol permeability coefficient reaches a minimum of 7.15×10−7 cm2 s−1, a 5-fold decrease compared with that of the pristine SPEEK. Despite the fact that the proton conductivity is decreased to some extent as a result of introduction of the silica, the hybrid membranes with silica content of 4–8wt.% shows higher selectivity than Nafion117. [Copyright &y& Elsevier]

[Display omitted] • Biochar-based fertilizer increases soil carbon pool and microbial carbon content. • Drip irrigation combined with biochar-based fertilizer reduces nitrogen use in crop production. • Biochar-based fertilizer improves plant photosynthetic rate and dry matter accumulation. • Soil easily oxidizable carbon content is significantly increased by biochar-based fertilizer. • Biochar-based fertilizer is an environmentally friendly and resource-saving approach in crop production. In order to explore a resource-saving and environmentally friendly approach to reduce nitrogen fertilizer and increase soil carbon pool in crop production. There are 5 treatments in the experiment namely CK: conventional fertilization and irrigation methods (pure nitrogen 30 kg/hm2); T1: drip irrigation fertilization method (pure nitrogen 15 kg/hm2); T2: drip irrigation fertilization method (pure nitrogen 15 kg /hm2), biochar-based fertilizer 600 kg/hm2; T3: drip irrigation method (pure nitrogen 15 kg/hm2), biochar-based fertilizer 1200 kg/hm2; T4: drip irrigation method (pure nitrogen 15 kg/hm2), biochar-based fertilizer is 1800 kg/hm2. The results showed that the microbial carbon content of the biochar-based fertilizer treatment under the condition of drip irrigation to reduce nitrogen was increased by 39.9%-68.4% as compared with the control. All treatments of the biochar-based fertilizer can significantly increase the soil easily oxidizable carbon in the early and mid-term growth. The content of solid carbon and soluble organic carbon increased by 31.3%-148.31% and 12.2%-63.92%, respectively. The application of biochar-based fertilizers significantly increased the net photosynthetic rate and stomatal conductance in the early and mid-transplanting period, as well as the transpiration rate and intercellular CO 2 concentration throughout the growth period, and the SPAD, NDVI value, and dry matter accumulation. Under the condition of reducing nitrogen by 50%, drip irrigation combined with biochar-based fertilizer can significantly increase the soil microbial biomass carbon content, oxidizable carbon and soluble carbon content, promote the photosynthetic effect and dry matter accumulation of tobacco plants, and it is beneficial to promote crop planting. [ABSTRACT FROM AUTHOR]

The usage of fertilizer with high nitrogen content in many countries, as well as its enormous surplus, has a negative impact on the soil ecological environment in agricultural system. This consumption of nitrogen fertilizer can be minimized by applying biochar to maintain the sufficient supply of nitrogen as nutrient to the near-root zone. This study investigated the effects of various amounts of biochar application (450, 900, 1350, and 1800 kg/hm2) and reduction of nitrogen fertilizer amount (10, 15, 20, and 25%) on the nutrients and microorganism community structure in rhizosphere growing tobacco plant. The microorganism community was found essential in improving nitrogen retention. Compared with conventional treatment, an application of biochar in rhizosphere soil increased the content of soil available phosphorus, organic matter and total nitrogen by 21.47%, 26.34%, and 9.52%, respectively. It also increased the abundance of microorganisms that are capable of degrading and utilizing organic matter and cellulose, such as Actinobacteria and Acidobacteria. The relative abundance of Chloroflexi was also increased by 49.67–78.61%, and the Acidobacteria increased by 14.79–39.13%. Overall, the application of biochar with reduced nitrogen fertilizer amount can regulate the rhizosphere microecological environment of tobacco plants and their microbial population structure, thereby promoting soil health for tobacco plant growth while reducing soil acidification and environmental pollution caused by excessive nitrogen fertilizer. [Display omitted] • Biochar can compensate N 2 fertilizer in supplying nutrient to rhizophere soil. • Biochar increases organic matter, phosphorus, and nitrogen in rhizophere soil. • Biochar favors a healthy rhizosphere microecological environment for plants. • Soil microbial diversity is enriched and provides active pool for plant nutrients. • Biochar with reduced N 2 fertilizer promote soil health with less acidification. [ABSTRACT FROM AUTHOR]

Most studies on the effects of biochar and fertilizer on soil carbon (C) and nitrogen (N) mineralization, and microbial C and N content, are restricted to a single soil type, limiting our understanding of the interactions between these factors and microbial functions. To address this paucity in knowledge, we undertook a 3-year experiment using four contrasting soils to assess the role of peanut shell biochar and fertilizer on C and N mineralization, microbial C and N, and N stoichiometry. Across all four soils, biochar significantly (P < 0.05) increased soil carbon mineralization (C min) and nitrogen mineralization (N min) over three years compared to fertilizer and the control. Biochar also increased total C (C soil) across the four soils in year 1, with the Fluvisol recording greater total C in year 2 and Phaeozem having greater total C in year 3. Biochar resulted in a higher microbial biomass C (C mic), total N (N soil) and microbial biomass N (N mic); the degree of change was closely related to C soil and N soil. There was a positive correlation between C mic :N mic and C soil :N soil ; while C soil and C mic increased following amendment with biochar, which reduced the soil C and N stoichiometric imbalance (N imb) caused by the increase in the C to N ratio. However, fertilizer exacerbated the imbalance of soil C and N stoichiometry. Fertilizer also reduced the C soil :N soil and C mic :N mic ratios. Soil pH had a positive correlation with C soil , C mic , N mic , C min , N min , C soil :N soil , C mic :N mic , and biochar increases this correlation. The soil pH was negatively correlated with C imb :N imb and N soil. Fertilizer was positively correlated C imb :N imb and N soil. In contrast, fertilizer N application lowered microbial biomass C:N. We conclude that biochar reduces the imbalance of soil C and N stoichiometry, whereas fertilizer increased this imbalance. Biochar had a greater impact on C and N in soils with a lower pH. Unlabelled Image • Biochar reduces the imbalance of soil C and N stoichiometry. • Fertilizers exacerbate the imbalance of soil C and N stoichiometry. • Biochar is conducive to the sustainable development of agriculture. • Biochar improves soil MBC content and C and N mineralization rate. • Changes of C and N indexes in different soils are closely related to soil pH. [ABSTRACT FROM AUTHOR]

• The association between soil microbiota and tobacco quality was studied after applying fertilizers. • Biochar and high-carbon fertilizers increased the aroma through changing the soil microbiota. • Forty microbial phylotypes involved in tobacco growth and aroma increasement. Fertilizers promote plant growth through increasing plant nutrition and changing soil microbial communities. Here, the association between soil microbial communities and tobacco (Nicotiana tabacum L.) quality was investigated via high-throughput MiSeq sequencing and LC-GC-MS after applying fertilizers in purple soil. Biochar + chemical fertilizer (BC) and a high-carbon fertilizer + chemical fertilizer (HC) improved soil properties, including soil carbon and nitrogen pool, and increased the aroma of tobacco leaves by 19.38 % and 28.90 %, respectively. Biochar and high-carbon fertilizer increased the microbial diversity and altered their distribution, including improvement of unique bacteria, and Chao1 and Shannon indexes. Linear discriminant analysis identified 40 key phylotypes in response to fertilizers, including plant growth-promoting bacteria such as the genera Sphingomonas , Pseudomonas, Sphingobium, Haliangium and families Rhizobiaceae and Micrococcaceae, which are potentially associated with the quality of soil and tobacco plants. This study elaborates the mechanism underlying tobacco quality improvement by fertilizers and provides understanding of the methods for improving tobacco aroma. [ABSTRACT FROM AUTHOR]