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[Display omitted] • A negative spiropyran with a visible light response is successfully synthesized. • Merocyanine diol is first used as an intelligent electrolyte. • A visible light sensor with a simple structure is successfully prepared. • A core-sheath flexible conductive fiber with visible light sensing is fabricated. Flexible conductive fibers have attracted significant attention in the wearable electronics field because of light weight, small size, and easy shape morphing. To date, there are few reports on multifunctional flexible conductive fibers. Finding a facile and effective solution for large-scale production of flexible conductive fibers is still a challenge. In this work, a flexible core-sheath fiber with excellent electrical conductivity (24.71 Ω·m) and visible light sensing is fabricated, which contains a merocyanine diol (MC(OH) 2)/CrCl 3 ·6H 2 O/ethanol aqueous solution core layer and a silicon rubber outer layer. The synthesized MC(OH) 2 is an intelligent molecular switch with a visible light response that can reversibly convert from open-form MC(OH) 2 to closed-form spiropyran diol (SP(OH) 2) after short visible light irradiation. In the reverse process, the transition from SP(OH) 2 to MC(OH) 2 can occur gradually in the dark. This can be used to sense visible light in addition to electrical conductivity. The reversible change in the electrical resistance of the MC(OH) 2 /CrCl 3 ·6H 2 O/ethanol aqueous solution reaches 15.59%. This fiber shows excellent electrical conductivity, good flexibility, a sensitive visible light response, good photochromism, a simple structure, low cost, easy preparation, and suitability for industrial large-scale production, offering promise for applications in the fields of flexible and wearable electronics. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of coordination bond and chain rigidity on the crystalline structure was discussed. • Novel polyimide films with low linear thermal expansion coefficients were made. • Mechanical Properties of polyimides were enhanced by introducing coordination bonds. Coordination bonds and chain rigidities play severe roles in crystalline structure and property of polyimides (PIs). This study developed various polyimides with metal-diimine coordination bonds and varying chain rigidities. How coordination bonds and chain stiffness affect the semi-crystalline structure of polyimide films was investigated. Results from Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra confirmed the successful synthesis of coordinated polyimide films. Wide-angle diffraction (WAXD) results revealed that the crystallization behavior of PIs with flexible chains is significantly affected by additional coordination bonds, while the crystallization of PIs with rigid structures is primarily influenced by the chain rigidities. Compared to coordinated PIs with amorphous structure, PIs with both coordination bonds and semi-crystalline structures exhibited enhanced heat resistance, crystallinity, and dimensional stability. Notably, the coordinated PI-BP-Cu film with the highest chain rigidity in this study demonstrated excellent mechanical properties, with a tensile strength of 280 MPa, initial modulus of 5.7 GPa, and outstanding dimensional stability, characterized by a linear thermal expansion coefficient of 8.9 ppm/K (40–300 °C). These findings significantly enhance its suitability for use in metal/non-metal bonding composite materials. [ABSTRACT FROM AUTHOR]

• A method to determine the productivity of ERC is proposed. • Dynamic model of roll was established. • Flow model of material in the crushing chamber was established. • Breakage model was established. Productivity, as one of the key indicators for assessing the performance of a crusher, holds significant importance in guiding production practices. It refers to the quantity of materials processed or the quality of output materials within a given time frame. However, there is currently limited research on eccentric roller crushers, and the calculation method for productivity is unclear, failing to consider the motion characteristics between the roller and the materials. To address these issues, this study analyses the motion mode of the crushing roller and establishes a dynamic model for the roll and a flow model for the material. Furthermore, a particle size distribution at the choke level has been established using the breakage model. Based on these models, a productivity calculation method for eccentric roll crushers is proposed. Then, the effectiveness of the method is verified through laboratory experiment. The results indicate that the proposed calculation method can effectively estimate the productivity of eccentric roll crushers. [ABSTRACT FROM AUTHOR]

In this work, the water-soluble polyethyleneimine (PEI) was grafted onto the blended polystyrene (PS) and dopamine (PS/DA) electrospun fiber by using polydopamine (PDA) as an intermediate layer (PS/DA@PDA@PEI) to develop the water purification material toward Congo red (CR) dye removal. The morphology and structure of the obtained fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Batch adsorption experiments were performed to investigate pH impacts, comparative adsorption, kinetics, isotherms, and thermodynamics. In comparison with PS/DA fibers and (PS/DA)@PDA fibers, the PS/DA@PDA@PEI fibers exhibited much higher CR adsorption capacity. The adsorption results also showed that the adsorption process toward CR by PS/DA@PDA@PEI fibers followed the Langmuir isotherm model and pseudo-second-order model. Meanwhile, the thermodynamic study revealed that CR removal was both spontaneous and endothermic. Further, the PS/DA@PDA@PEI loaded with CR can be recycled with HCl solution, which can be used repeatedly for CR adsorption. This work indicates that PS/DA@PDA@PEI fibers have great potential to be used as promising adsorbents for CR removal from water. [Display omitted] • A multifunctional (PS/DA)@PDA@PEI electrospinning nanofibrous membrane has been developed by firmly anchored PDA and PEI. • The modified nanofibrous membrane of (PS/DA)@PDA@PEI exhibited high efficiency as an adsorbent for GR removal. • Adsorption occurred mainly by electrostatic attraction and hydrogen bonding. • Isotherms, kinetic models, and thermodynamic parameters were investigated. [ABSTRACT FROM AUTHOR]

Constructing fully rigid chain polyimides with reversible sol-gel/gel-sol transition is significant for developing high-performance and functional materials. π-π stacking, a typical weak interaction, has attracted great interest in producing functional gels, but less has been reported in polyimide organogels. This work developed new polyimide organogels using π-π interactions by incorporating bisbenzoxazole moieties with fully coplanar structures in polyimides. The reversible sol-gel transition behavior with temperature and strain response was systematically studied using rheological methods. DFT simulations, temperature-dependent NMR, UV–Vis, and fluorescence spectroscopy results confirmed the existence of the dynamic π-π interactions in polyimides. Based on the success, we further combined sol-gel methods and non-solvent phase separation methods to prepare a new type of nanofiltration (NF) membranes. The resulting NF membranes showed a higher rejection of methylene blue (rejections of 99.6%) and a good permeability of sodium salt (rejections of 5.1–7.7%), showing great promise for selective filtration of industrial dye wastewater. [Display omitted] • Novel PI organogels were prepared by constructing π-π interactions. • NF membranes with good desalination ability were made. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel polyimide-based nanofiltration membranes were prepared by constructing dual coordination interactions. • The skin and supporting layers of NF membranes can be controlled by designing coordination interactions. • Nanofiltration membrane performance optimized by controllable microstructure. Polyimide-based nanofiltration membranes (NF) featuring customizable chemical structure and outstanding comprehensive performance have garnered tremendous interest for potential applications in ions rejection. Coordinated interactions can build supramolecular networks in polyimide that reshuffle phase separation behavior during membrane formation, thus conferring microstructural flexibility to nanofiltration membranes. In this paper, novel nanofiltration membranes were prepared by constructing dual coordination interactions in polyimide, and the structures were confirmed by NMR, FTIR, EDX, and XPS analyses. As expected, the skin and supporting layers of the PI-based NF membranes can be controlled by designing coordination conditions during membrane formation. A promising result is that the resulted NF membranes occur higher reject of metal ions than the pristine membranes prepared by conventional non-solvent induced phase separation methods. The optimized performance showed significantly higher permeability for removing Mg2+ ions, giving water permeance of 477.7 L m−2 h−1·bar−1 and a rejection of over 80%. Moreover, the resulted PI-based NF membranes occur better solvent resistance than the pristine NF membranes due to the enhanced coordination structures. As a preliminary study, this work gives a new strategy to regulate the microstructure of nanofiltration membranes, promising further potential for applications in ion removal. [ABSTRACT FROM AUTHOR]

Vehicle detection is a major part of a driver assistant system. However, a complex environment and diverse types of vehicles make real-time detection of vehicles a very challenging task. This paper proposes a real-time vehicle detection system of two steps: hypothesis generation and hypothesis verification. In the first step, potential vehicles are detected using shadows under vehicles. In the second step, hypotheses generated in the first step are classified as vehicles and non-vehicles. The novel aspect of this research is in constructing two types of histogram orientation gradients descriptors to extract vehicle features, and then combining them for their final features. The AdaBoost classifier is trained by the combined histogram orientation gradients features. The Treatment Group of images vehicle dataset is adopted for the classifier training. The experiment results show that the proposed system performs well in accuracy and robustness and can meet real-time requirements. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study is to evaluate the power, efficiency and emissions of an electronic-controlled single-cylinder engine fueled with pure natural gas and natural gas–hydrogen blends, respectively. Replacing the nature gas with hydrogen/methane blend fuels was found to have a significant influence on engine performance. The effects of excess air ratio and spark timing were discussed. The results show that under certain engine conditions the maximum cylinder gas pressure, maximum heat release rate increased with the increase of hydrogen fraction. The increase of hydrogen fraction in the blends contributed to the increase of NO x and the decrease of HC and CO. The brake specific fuel consumption decreased with the increase of hydrogen fraction. Using HCNG at relatively leaner fuel–air mixtures and retarded spark timing totally improved the engine emissions without incurring the performance penalty. [Copyright &y& Elsevier]