The Fe-based coating was produced on the surface of the column substrate with a Al2O3 cylindrical sleeve by high frequency induction cladding, microstructure of the coating was investigated with ...scanning electron microscope (SEM), the crystal structure was characterized by X-ray diffractometer (XRD), the microhardness and wear resisitance of the coating were evaluated. The results show that a metallurgical bond between coating and substrate was obtained during the rapid solidification, the phases of the coating were composed of austenite and the eutectic of gamma -Fe + (Cr, Fe)7(C, B)3. Compared with the substrate, the microhardness and wear resistance of the coating improved apparently, solid-solution strengthening and second-phase particle hardening led to these results.
The gossamer-like Nb
2
O
5
-RGO nanocomposite was synthesized through a solvothermal treatment, and the Nb
2
O
5
nanoparticles were uniformly coated on the RGO sheets. The size of the Nb
2
O
5
...nanoparticles is about 200–700 nm. The applications of Nb
2
O
5
-RGO as supercapacitor were then explored systematically. The morphology, textural structure, and physicochemical property of Nb
2
O
5
-RGO were investigated by using SEM, TEM, XRD, FT-IR, TG, and Raman. The electrochemical performance of RGO, Nb
2
O
5
, and Nb
2
O
5
-RGO was assessed through CV and galvanostatic charge-discharge test. The experimental results show that gossamer-like Nb
2
O
5
-RGO exhibits partial faradic pseudocapacitance and good electrical double layer capacitance property. The specific capacitance value 299.23 Fg
−1
of Nb
2
O
5
-RGO nanocomposite is about 2.7 and 1.7 times higher than that of Nb
2
O
5
and RGO, retaining 87.72% of its initial capacitance after 2000 cycles under the optimized conditions, which demonstrate that more ordered binary architecture Nb
2
O
5
-RGO nanocomposite along with easy synthesis possesses faster charge-discharge kinetics and excellent supercapacitive performance.
The potential transmission of antibiotic resistance genes (ARGs) from the rhizosphere to plants and humans poses a significant concern. This study aims to investigate the distribution of tetracycline ...resistance genes (TRGs) in rice using four genotypes and identify the primary source of TRGs in grains. Quantitative polymerase chain reaction (qPCR) was employed to determine the abundance of seven TRGs and intI1 in four rice varieties and three partitions during the jointing and heading stages, respectively. The analysis of the bacterial community was conducted to elucidate the underlying mechanism of the profiles of TRGs. It was observed that tetZ was predominantly present in the rhizosphere and endoroot, whereas tetX became dominant in grains. The relative abundances of TRGs and intI1 exhibited significant variations across both the variety and partition. However, no significant differences were observed in grains, where the abundances of TRGs were several orders of magnitude lower compared to those in the rhizosphere. Nevertheless, the potential risk of the dissemination of TRGs to humans, particularly those carried by potential pathogens in grains, warrants attention. The increased likelihood of TRGs accumulation in the rhizosphere and endoroot of hybrid rice varieties, as opposed to japonica varieties, may be attributed to the heightened metabolic activities of their roots. The significant associations observed between intI1 and TRGs, coupled with the substantial alterations in potential hosts for intI1 across various treatments, indicate that intI1-mediated horizontal gene transfer plays a role in the diverse range of bacterial hosts for TRGs. The study also revealed that rhizosphere bacteria during the jointing stage serve as the primary contributors of TRGs in grains through the endoroot junction. The findings indicate that Japonica rice varieties exhibit superior control over TRGs compared to hybrid varieties, emphasizing the need for early interventions throughout the entire growth period of rice.
Ultrafiltration membrane harvesting of Scenedesmus acuminatus was tested using alternative feed (AF) directions, i.e., bottom feed-top feed cycle and traditional bottom feed (BF). Both operations ...were investigated to compare the membrane performance and membrane fouling in microalgal harvesting process by scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM) and Fourier transform infrared (FTIR). The results showed that when the AF was used with and without backwashing, average flux increased by 27.9% and 17.9%, respectively, comparing with BF (68 L m−2 h−1) and the final dry weight reached 197 g L−1 and 175.8 g L−1, respectively. Microalgal cell deposition on AF membrane was reduced from 1.44 × 105 cell cm−2 on BF membrane to 7.12 × 104 cell cm−2 on AF membrane, according to SEM observation. The protein and polysaccharides on the AF membrane surface were also reduced according to CLSM and FTIR analysis. Fouling analysis along the fiber length revealed that fouling was most severe at the top section for BF as a result of a lower shear rate at the outlet. AF operation generated dynamic filtration by frequently switching flow directions, increasing the shear rate at both the top and bottom of the fibers, and therefore filtration and clean process simultaneously provided good performance.
Display omitted
•The hypothesis of membrane fouling differs along the fiber length was confirmed.•Dynamic filtration with alternative feed direction alleviated fouling.•Microalgal cell deposition and protein/polysaccharide attachment were reduced.•Scenedesmus acuminatus was concentrated 179 times (197 g L−1), flux of 87.0 Lm−2 h−1 was obtained.
PDF
