Lightweight design of an electric bus body structure with analytical target cascading

Lightweight designs of new-energy vehicles can reduce energy consumption,thereby improving driving mileage.In this study,a lightweight design of a newly developed multi-material electric bus body structure is examined in combination with analytical target cascading(ATC).By proposing an ATC-based two-level optimization strategy,the original lightweight design problem is decomposed into the system level and three subsystem levels.The system-level optimization model is related to mass minimization with all the structural modal frequency constraints,while each subsystem-level optimization model is related to the sub-structural performance objective with sub-structure mass constraints.To enhance the interaction between two-level systems,each subsystem-level objective is reformulated as a penalty-based function coordinated with the system-level objective.To guarantee the accuracy of the model-based analysis,a finite element model is validated through experimental modal test.A sequential quadratic programming algorithm is used to address the defined optimization problem for effective convergence.Compared with the initial design,the total mass is reduced by 49 kg,and the torsional stiffness is increased by 17.5%.In addition,the obtained design is also validated through strength analysis.

Interactions between lead(Ⅱ) ions and dissolved organic matter derived from organic fertilizers incubated in the field

This work was to study composition characteristics and the subsequent effect on the lead(Pb) binding properties of dissolved organic matter(DOM) derived from seaweed-based(SWOF) and chicken manure organic fertilizers(CMOF) during a one-year field incubation experiment using the excitation-emission matrix-parallel factor(EEM-PARAFAC) and twodimensional correlation spectroscopy(2DCOS) analysis. Results showed that high aromatic and hydrophobic fluorescent substances were enriched in CMOF-derived DOM and SWOFderived DOM and enhanced over time. And phenolic groups in the fulvic-like substances for SWOF-derived DOM and carboxyl groups in the humic-like substances for CMOF-derived DOM had the fastest responses over time, respectively. Moreover, both non-fluorescent polysaccharides and fluorescent humic-like substances or fulvic-like substances with aromatic(C=C) groups first participated in the binding process of Pb to SWOF-derived DOM on day 0 and 180 during the lead binding process. In contrast, humic-like substances associated with aromatic(C=C) and phenolic groups gave a faster response to Pb binding on day 360. Regarding CMOF-derived DOM, the fulvic-like substances associated with aromatic(C=C) and carboxylic groups displayed a faster response to Pb ions on day 0. Nonetheless,polysaccharides and humic-like associated with phenolic groups had a faster response on days 180 and 360. It is noteworthy that the polysaccharides, which participated in Pb binding to CMOF-derived DOM, posed a higher risk of Pb in the environment after 360 days. Therefore, these findings gave new insights into the long-term applications of commercial organic fertilizers for the amendment of soil.