Control Research of Dual Chamber Hydro-Pneumatic Suspension

Vehicle riding comfort and handling stability are directly affected by suspension performance.A novel dual chamber hydro-pneumatic(DCHP)suspension system is developed in this paper.Based on the structural analysis of the DCHP suspension,an equivalent suspension model is proposed for the control purpose.A cuckoo search(CS)based fuzzy PID controller is proposed for the control of the DCHP suspension system.The proposed controller combines the advantage of fuzzy logic and PID controller,and CS algorithm is used to regulate the membership functions and PID parameters.Compared with tradition LQR controller and passive suspension system,the CSFPID controller can reduce the sprung mass acceleration,and at the same time with no deterioration of tire deflection.

Macro and micro grouting process and the influence mechanism of cracks in soft coal seam

Grouting is an important method to reinforce soft coal roadway,and the presence of primary cracks in the coal body has an important influence on the grouting effect.With the discrete element simulation method,the grouting process of the soft coal seam was simulated.The mechanism of primary cracks on grouting was revealed,while the influence of fracture characteristics and grouting pressure on the grouting effect was analyzed.The results demonstrated that grouting in the soft coal seam involves the stages of seepage,rapid splitting,slow splitting,and stability.Due to the presence of primary cracks,the grouting diffusion radius increased significantly.Under the slurry pressure,the tensile stress concentration was formed at the crack tip,and the slurry split the coal once the splitting pressure was reached.In addition,the distribution characteristics of fractures are found to have a great influence on the grouting effect.It is observed that smaller fracture spacing is associated with a larger slurry diffusion radius and thus easier penetration of the primary crack tips.The fracture angle affects the direction of fracture propagation.The secondary fracture formed by splitting is a tensile fracture,which is more likely to extend along the direction parallel to the maximum principal stress.Overall,these simulation results have guiding significance for the setting of reasonable spacing of grouting holes in the practice of grouting engineering.

Flexible interdigitated layered framework with multiple accessible active sites for high-performance CH_(3)I capture

The development of adsorbent materials for effective capture of radioactive iodomethane(CH_(3)I) from the off-gas of used nuclear fuel reprocessing, remains a significant and challenging line of research because currently state-of-art adsorbents still suffer from low binding affinity with CH_(3)I. Here, we proposed a brand-new adsorption topological structure by developing a 2D interdigitated layered framework, named SCU-20, featuring slide-like channel with multiple active sites for CH_(3)I capture. The responsive rotating-adaptive aperture of SCU-20 enables the optimal utilization of all active sites within the pore for highly selective recognition and capture of CH_(3)I. A record-breaking CH_(3)I uptake capacity of 1.84 g/g was achieved under static sorption conditions with saturated CH_(3)I vapor. Both experimental and theoretical findings demonstrated that the exceptional uptake of SCU-20 towards CH_(3)I can be attributed to the confined physical electrostatic adsorption of F sites, coupled with the chemical nitrogen methylation reaction with uncoordinated N atoms of pyrazine. Moreover, dynamic CH_(3)I uptake capacity potentially allows for the capture of CH_(3)I in simulated real-world off gas reprocessing conditions. This study highlights the potential of SCU-20 as a promising candidate for efficient capture of iodine species and contributes to the development of effective solutions for radioactive iodine remediation.

Efficient and selective H_(2)O_(2)production through uranyl-assisted photocatalytic oxygen reduction reaction process in a uranium-organic framework

Harnessing solar energy by photocatalytically converting oxygen and water into high-value-added H_(2)O_(2)is a promising way of alleviating both environmental and energy issues.It is worth noting that suppressing detrimental side reactions,such as the generation of·O_(2)^(-),is a critical approach to enhancing H_(2)O_(2)production.Herein,a 2-fold interpenetrating 3D uranium-organic framework(YTU-W-1)was developed and introduced for photocatalytic H_(2)O_(2)production.The material demonstrates a different photocatalytic mechanism when employing uranyl as an initiator,as compared with the conventional semiconductor photocatalytic pathway involving photo-generated charge carriers.Benefiting from the strong hydrogen abstraction effect of the U≡O·and the direct one-step oxygen reduction pathway,YTU-W-1 exhibits enhanced photocatalytic performance for H_(2)O_(2)production with yield efficiency of 221μmol h-1g-1.Furthermore,YTU-W-1 displays a high H_(2)O_(2)selectivity of 68%,confirmed by rotating ring-disk electrode(RRDE)measurement.DFTcalculations were used to elucidate the critical role of uranyl in the photocatalytic oxygen reduction reaction for H_(2)O_(2)production.This research introduces an innovative approach to photo-driven H_(2)O_(2)production,underscoring the potential for heterogeneous catalysts to engage in photocatalytic reactions independently of photogenerated charge carriers.

Reliability analysis based on a novel density estimation method for structures with correlations

Estimating the Probability Density Function（PDF） of the performance function is a direct way for structural reliability analysis,and the failure probability can be easily obtained by integration in the failure domain.However,efficiently estimating the PDF is still an urgent problem to be solved.The existing fractional moment based maximum entropy has provided a very advanced method for the PDF estimation,whereas the main shortcoming is that it limits the application of the reliability analysis method only to structures with independent inputs.While in fact,structures with correlated inputs always exist in engineering,thus this paper improves the maximum entropy method,and applies the Unscented Transformation（UT） technique to compute the fractional moments of the performance function for structures with correlations,which is a very efficient moment estimation method for models with any inputs.The proposed method can precisely estimate the probability distributions of performance functions for structures with correlations.Besides,the number of function evaluations of the proposed method in reliability analysis,which is determined by UT,is really small.Several examples are employed to illustrate the accuracy and advantages of the proposed method.

Synergy of first-and second-sphere interactions in a covalent organic framework boosts highly selective platinum uptake

Platinum recovery from waste electrical and electronic equipment(WEEE) in highly acidic solutions is significant to the electronics industry and environmental remediation. However, the lack of ingenious design and synergetic coordination gives rise to unsatisfied PtCl_(4)^(2-)extraction capacities and selectivities in most previously reported adsorbents(e.g., polymeric and inorganic materials). Herein, we proposed a synergistic strategy that realizes highly selective PtCl_(4)^(2-)uptake through first-and second-sphere coordinations. The proof-of-concept imine-linked covalent organic framework(SCU-COF-3) was found to chelate Pt Cl42-via the direct N…Pt coordination and the synergistically interlaminar N–H…Cl hydrogen bonds, which was disclosed by the comprehensive analysis of extended X-ray adsorption fine structure(EXAFS) characterizations and density functional theory(DFT) calculations. The unique adsorption mechanism imparts a superior adsorption capacity(168.4 mg g-1)and extraordinary Pt(II) selectivity to SCU-COF-3 under static conditions. In addition, SCU-COF-3 exhibits an upgraded distribution coefficient of 1.62 × 10^(5)mL· g^(-1), one order of magnitude higher than those of reported natural adsorbents. Specifically, SCU-COF-3 can extract PtCl_(4)^(2- )quantitatively from a simulated acidic waste solution coexisting with other 12 competitive ions, suggesting its promising application in practical scenarios.