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The CaCO3 interlayer was grown in situ on PK membrane through mineralization process, which plays a multi-functional role in the process of regulating IP and facilitating the formation of a thinner selective layer with rough and loose structure.

Organic solvent nanofiltration (OSN) is an emerging membrane separation technology, which urgently requires robust, easily processed, OSN membranes possessing high permeance and small solutes-selectivity to facilitate enhanced industrial uptake. Herein, we describe the use of two 2,2′-biphenol (BIPOL) derivatives to fabricate hyper-crosslinked, microporous polymer nanofilms through IP. Ultra-thin, defect-free polyesteramide/polyester nanofilms (≈5 nm) could be obtained readily due to the relatively large molecular size and ionized nature of the BIPOL monomers retarding the rate of the IP. The enhanced microporosity arises from the hyper-crosslinked network structure and monomer rigidity. Specifically, the amino-BIPOL/PAN membrane exhibits extraordinary permselectivity performances with molecular weight cut-off as low as 233 Da and MeOH permeance of ≈13 LMH/bar. Precise separation of small dye mixtures with similar M.W. based on both their charge and molecular size are achieved.

Highly permeable organic solvent nanofiltration (OSN) membranes are desired to be used in an efficient and energy-saving chemical separation process. Herein, we fabricated a high-flux OSN membrane by synthesizing 7,7′-dihydroxy-2,2′-binaphthol (7,7′-OH-BINOL) as an aqueous phase monomer to react with trimesoyl chloride (TMC) via interfacial polymerization. The unique structures of 7,7′-OH-BINOL having a rotatable highly kinked unit and a rigid binaphthol ring endow the fabricated polyarylate membrane with very high microporosity and super-high Young's modulus. Both simulated and experimental results demonstrate that the BINOL-based polyarylate (PAR-BINOL) membrane has two types of micropores including cross-linked pores and stacked pores. Our results find that the PAR-BINOL membrane exhibits very high solvent permeance over a wide range of solvents with diverse polarity, and also possesses a long-term stable separation performance in solvents. Impressively, the membrane solvent permeance can reach up to 28.7 L m−2 h−1 bar−1, 9.2 L m−2 h−1 bar−1 and 6.7 L m−2 h−1 bar−1 for acetone, methanol, and dimethylformamide (DMF), respectively. The rejection of tetracycline (TC, Mw = 444 g mol−1) is 98.2%. Our work provides some insights into the molecular engineering of monomers with unique contorted and rigid structures for the fabrication of highly permeable OSN membranes.

Numerical simulation of heating process of different materials under microwave irradiation has been widely studied. This study reviews the model development of microwave heating under different application scenarios in recent years, new CFD models for microwave-assisted gasification of biomass are also introduced. The results show that more accurate simulation results can be obtained by properly adjusting the improved model according to the different situations. When the structure of the object in the microwave field is relatively simple, one-dimensional or two-dimensional processing can be used in the model construction to simplify the calculation. When there is phase change during the microwave heating process, it is more helpful to improve the corresponding mass transfer model and consider the volume change to obtain accurate simulation results. When the heated object is moving, choosing appropriate boundary conditions can simplify the calculation and improve the accuracy of simulation results. The contents detailed in this review not only introduce the model development of microwave heating, but also present the simulation results of microwave-assisted gasification of biomass.

Microwave-assisted heating is an effective heating method for thermochemical conversion of biomass. In this study, experimental syngas production from microwave-assisted air gasification of biomass in a fluidized bed reactor at different gasification temperatures, equivalence ratios and silicon carbide loads, was studied and reported. The results showed that the highest syngas yield (78.2 wt%), higher heating value (6.3 MJ/Nm

Rice is the primary staple for the world’s population and it is one of the main cereals in the world. The tremendous global rice production results in a huge amount of rice husk, making rice husk a very important biomass fuel. LHV (lower heating value) and exergy are two important properties of a biomass fuel, and they are generally used for evaluating the energy of a biomass fuel. Also, exergy is usually used to assess the energy quality of a biomass fuel. This study aims to investigate the LHV and exergy of rice husk. The LHVs and exergy values of twenty eight rice husk samples are investigated in this study. The results show that the LHVs and exergy values of the rice husk samples are in the ranges of 8879.12–16200.00 kJ/kg and 10918.01–18457.87 kJ/kg, respectively. The higher LHV of a rice husk the higher exergy of the rice husk, and a positive linear relationship between exergy and LHV is observed for the rice husk samples. The relative errors between the estimated and calculated exergy values are in the range of −3.678%–1.704% for the rice husk samples, the simple relationship proposed in this study can therefore be used as an expeditious methodology for estimating the exergy of rice husks.

Performances of high density polyethylene (HDPE) plastic particles heated in a microwave chamber were detailed and the effects of chamber volume (100 ml, 150 ml, and 200 ml), feeding load (10 g, 20 g, and 30 g), and microwave power (500 W, 700 W, and 900 W) were investigated. The results showed that the temperatures of HDPE plastic particles increased to 220.2 °C, 288.3 °C and 352.3 °C during the sixty minutes for the 100 ml, 150 ml and 200 ml chamber volumes, and the average heating rates were 3.36 °C/min, 4.49 °C/min and 5.5 °C/min, respectively. The temperatures of HDPE plastic particles increased to 150.8 °C, 155.4 °C and 220.2 °C for the 10 g, 20 g and 30 g feeding loads, and the average heating rates were 2.22 °C/min, 2.29 °C/min and 3.36 °C/min, respectively. The temperatures of HDPE plastic particles increased to 161.5 °C, 192.8 °C and 220.2 °C for the 500 W, 700 W and 900 W microwave powers, and the average heating rates were 2.38 °C/min, 2.89 °C/min and 3.36 °C/min, respectively. Equations were proposed to estimate the temperatures, and the relative errors were mainly between −16.46% and 16.03%.

Microwave heating performances of low density polyethylene (LDPE) plastic particles as affected by microwave power (500, 700, and 900 W), feeding load (10, 20, and 30 g), and chamber volume (100, 150, and 200 ml) were investigated and detailed in this study. The results showed that the temperatures of LDPE plastic particles increased to 159.8, 259.1 and 314.4 oC during the sixty minutes for the 500, 700 and 900 W microwave powers, and the average heating rates were 2.34, 3.96 and 4.89 oC/min, respectively. The temperatures of LDPE plastic particles increased to 140.8, 278.7 and 314.4 oC for the 10, 20 and 30 g feeding loads, and the average heating rates were 2.03, 4.28 and 4.89 oC/min, respectively. The temperatures of LDPE plastic particles increased to 314.4, 238.9 and 184.8 oC for the 100, 150 and 200 ml chamber volumes, and the average heating rates were 4.89, 3.68 and 2.76 oC/min, respectively. Equations were proposed to estimate the temperatures, and the relative errors were mainly between − 18.04% and 9.10%.

Zwitterions have been attracting great attention for researchers to tailor the separation membranes featuring enhanced water permeability and excellent antifouling property. Here we functionalized polyamide membrane surface with small-molecule zwitterions through sequential interfacial polymerization (SIP) technique to improve the performance of RO membranes. Zwitterionic molecules 3-(4-(2-((4-aminophenyl)amino)ethyl)morpholino-4-ium)propane-1-sulfonate (PPD-MEPS) and amino acid arginine were covalently bonded onto the PA surface via the amine groups of two zwitterions. Consequently, the surface hydrophilicity of both modified membranes were significantly improved with WCA decreased from ~60° to ~28°, and their surface negative charge also decreased to some extent at high pH values. The water permeability increased from 2.45 LMH/bar to 3.81–3.85 LMH/bar, increasing by about 57%, while maintained a NaCl rejection as high as 98.5%. In addition, the zwitterions-modified RO membranes exhibited much improved antibacterial attachment (E.coil) and fouling resistance to model foulants bovine serum albumin (BSA), lysozyme (LYZ) and humic acid (HA). Therefore, the facile zwitterions modified membranes possessing high water permeability and excellent antifouling performance, especially using amino acid Arg may find their potential promising application in water treatment.

A fluidized bed system was demonstrated and the fluidization performances of silicon carbide in the fluidized bed system were experimentally studied as to facilitate the further application of microwave-assisted fluidized bed. The results show that the smaller silicon carbide particles (0.25–1 mm) have better fluidization performances than larger ones (1–1.5, 1.5–2, 2–2.5 and 2.5–3 mm) due to the fact that the smaller particles are nearly spherical whereas the larger particles are irregular in shape (long and branched), and larger particles tend to form channels in fluidization. Fluidization velocity is too high, large bubbles will be generated to affect the uniformity of fluidized particles. The loading of fluidized particles should match that of the fluidized bed, and too low loading amount wastes the space of the fluidized bed, while too high loading amount will also produce large bubbles. For the fluidized bed system developed in this study, the suggested fluidization parameters were: (a) silicon carbide particle size of 0.25–1 mm, (b) fluidization velocity of 0.47–-0.71 m/s, and (c) silicon carbide particle loading of 40–50 g.

Fluidization is an effective method to better help the transfer and conversion of fuel particles. In this study, intensification of the fluidization performances of polypropylene was experimentally investigated by using microwave absorbent. The fluidization performances of polypropylene (PP) were initially presented and the effects of microwave absorbent (SiC) particle size, mass ratio of SiC to PP, and fluidization velocity on the co-fluidization performances were studied and presented. The results showed that the PP load significantly increased the initial bed height whereas slightly increased the critical fluidization velocity and bed expansion ratio. Adding microwave absorbent (SiC) can effectively improve the fluidization performance of PP particles. The smaller SiC particles (0.25−1 mm) had better fluidization performances than the larger ones (1–1.5 mm and 1.5−2 mm). The mass ratio of silicon carbide to polypropylene decreased the critical fluidization velocity. Fluidization velocity significantly affected the co-fluidization performance. For the co-fluidization of polypropylene and silicon carbide in the designed fluidized bed, the recommended fluidization parameters were: (a) the particle size of silicon carbide of 0.25–1 mm, (b) the mass ratio of silicon carbide to polypropylene of 3:2, and (c) the fluidization velocity of 0.66 m/s.

Field investigations have demonstrated that the wear life of a carbon slider of a pantograph in a high-speed train of the 250 km/h speed class is very short. In this study, several experimental tests were performed on a high-speed test machine to understand the mechanisms of the serious wear of the slider against the wire under electric current. The experiments on the high-speed railway were carried out at electric currents of 200, 300, 400, and 500 A, sliding speeds of 100, 150, 200, and 250 km/h, and normal loads of 60, 80, 100, and 120 N. The friction coefficient, wear volume, arc electric current, arc electric voltage drop, and temperature increase of the carbon slider were recorded and analyzed. The experimental results demonstrated that the wear volume of the slider increased with the electric current and that arc melting and thermally enhanced wear were the dominant mechanisms causing the serious wear of the slider.

α-Fe2O3@C core–shell nanorings are prepared by a facile large-scale two-step route incorporating a hydrothermal method and a carbon coated progress. Its structure and morphology are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope, and thermogravimetry. It is found that the as-prepared composite is composed of α-Fe2O3@C nanorings of about 148 nm in outer diameter, 50 nm in thickness, and 115 nm in length. These α-Fe2O3@C nanorings are enwrapped with ∼3 nm thick carbon shell. And the electrodes exhibit longer cycle life (815 mAhg−1 after cycling 160 times) at high current rate (1000 mAg−1) compared with that of bare α-Fe2O3 nanorings (810 mAhg−1 after cycling 30 times). The improved performance of the composite is attributed to the bondage from carbon shell, which can enhance the electronic conductivity and structural stability of α-Fe2O3 nanorings.