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A Machine Learning Approach for Segmentation and Characterization of Microtextured Regions in a Near-α Titanium Alloy

The development of automated segmentation and quantitative characterization of microtextured regions (MTRs) from the complex heterogeneous microstructures is urgently needed, since MTRs have been proven to be the critical issue that dominates the dwell-fatigue performance of aerospace components. In addition, MTRs in Ti alloys have similarities to microstructures encountered in other materials, including minerals and biomaterials. Meanwhile, machine learning (ML) offers new opportunities. This paper addresses segmentation and quantitative characterization of MTRs, where an ML approach, the Gaussian mixture models (GMMs) coupled with density-based spatial clustering of applications with noise (DBSCAN) clustering algorithms, was employed in order to process the orientation data acquired via EBSD in the Matlab environment. Pixels with orientation information acquired through electron backscatter diffraction (EBSD) are divided and colored into several “classes” (MTRs) within the defined c-axis misorientations (i.e., 25°, 20°, 15°, 10°, and 5°), the precision and efficacy of which are verified by the morphology and pole figure of the segmented MTR. An appropriate range of c-axis misorientations for MTR segmentation was derived, i.e., 15~20°. The contribution of this innovative technique is compared with previous studies. At the same time, the MTRs were statistically characterized in the global region.

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Thin film composite polyesteramide membrane with the incorporation of rigidly-contorted binaphthol-based monomer for enhanced nanofiltration separation performance

High-performance nanofiltration (NF) membranes prepared by interfacial polymerization (IP) are ideal choice for solving water scarcity. In this study, 7,7′-dihydroxy-2,2′-binaphthol (7,7′–OH-BINOL) with rigidly-contorted structure was used as a co-monomer with piperazine (PIP), leading to NF membranes with lower selective layer thickness and enhanced microporosity, thus facilitated the water molecules transportation. The incorporation of 7,7′–OH-BINOL could regulate the interface diffusion rate of PIP and afforded the polyesteramide selective layer with a special bowl-shaped crater surface morphology. The PIP/BINOL-TMC nanofiltration membrane with the optimal phenol/amine ratio presented water permeability of up to 17.01 L m-2 h−1 bar−1, which was more than two times that of the pristine NF membrane (i.e. PIP-TMC). Meanwhile, it displayed comparable Na2SO4 rejection (∼98%) and excellent mono-/divalent salt selectivity (SNaCl/Na2SO4 = 44). In addition, long-term operation and pressure resistance test results demonstrated that the tailored membrane had good operational stability. In conclusion, this work provides a feasible way to overcome the perm-selectivity trade-off effect of NF membrane and potentially could be used to solve the water scarcity problem.

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Organosilicon‐functionalized polyolefins, a kind of designable and versatile polymer: From preparation to applications

AbstractFunctionalization of polyolefins has been a challenging but promising issue since their invention, with the promise of retaining inherent properties and overcoming the low reactivity and poor compatibility. Organosilicons are widely used for polymer modification to improve thermal stability, hydrophobicity, compatibility, and permeability. Since the advent of alkoxysilane‐grafted polyethylene in 1960s, organosilicon‐functionalized polyolefins (Si‐PO) have been extensively prepared, investigated, and developed. The structure of Si‐PO is designable due to the flexible chemistry of organosilicons; crosslinked, long chain branched, and star‐shaped polyolefins are available after the introduction of alkoxysilanes, chlorosilanes, hyrdosilanes, or alkylsilanes into polyolefins, and generally these polymers are more compatible to fillers than commercial polyolefins due to stronger interaction. In addition, functionalization of polyolefins with stable organosilicon components such as polysiloxane and polysilsesquioxane can improve thermostability, hydrophobicity, gas permeability, and aging resistance; such polyolefins are usually grafted or block polymers. In this review, Si‐PO is classified according to the functional organosilicon component, namely alkoxysilane, chlorosilane, hydrosilane, alkylsilane, polysiloxane, and polysilsesquioxane; their preparations are discussed minutely and summarized with manifold examples. Silicon‐containing structures impart the unique properties of organosilicons to polyolefins; applications of Si‐PO as compatibilizers, processing aids, battery separators, and separating membranes have been widely reported and are discussed here.

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The acute toxicity, mechanism, bioconcentration and elimination of fluxametamide on zebrafish (Danio rerio)

Fluxametamide is a completely novel and the first isoxazoline insecticide used to control agricultural pests and has high insecticidal properties. To expand its usage in the paddy field, its potential toxicological effects on fish are necessary to make clear. In this study, the acute toxicity, bioconcentration and elimination of fluxametamide to zebrafish Danio rerio, and the action mode of it on the heteromeric Drα1β2Sγ2 and Drα1β2S GABA receptor was respectively determined by HPLC and two-electrode voltage clamp technique.Fluxametamide exhibited high toxicity to D. rerio, whereas slightly inhibited the GABA-stimulated current of Drα1β2Sγ2 or Drα1β2S. It showed high bioconcentration level in D. rerio at 0.0314 mg L−1 and 0.157 mg L−1, with bioconcentration factors at steady state of 1491.55 and 2875.28, respectively. The concentration of fluxametamide in D. rerio rapidly decreased from 47.84 ± 0.12 to 9.77 ± 1.13 mg kg−1 in 0.0314 mg L−1 or from 393.19 ± 0.46 to 46.93 ± 2.88 mg kg−1 in 0.157 mg L−1 within 10 days, and steadily kept at a low level after 18 days.In conclusion, fluxametamide has highly acute toxicity to D. rerio, and might induce high bioconcentration in a short time. As we know, this is the first report to provide a theoretical basis for evaluating the potential risk of fluxametamide on fish, and guidance for the application of fluxametamide.

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A novel electrochemical sensor based on N, S co-doped liquorice carbon/functionalized MWCNTs nanocomposites for simultaneous detection of licochalcone A and liquiritin

In this study, nanoporous C was prepared from the roots, stems and leaves of liquorice and modified via element doping. Then, the nitrogen and sulfur co-doped liquorice carbon (N, S-LC) and functional multiwall carbon nanotubes (f-MWCNTs) were dispersed using an ultrasonic dispersion technology, and a binary nanocomposite was prepared. N, S-LC plays a key role in the formation and electrochemical efficiency of binary nanocomposites, and electrochemical impedance spectroscopy indicates that the binary complexes formed by the hybridisation of N, S-LC and f-MWCNTs can improve the electron transfer ability of an electrode. The electrochemical behaviour of Licochalcone A (LicA) and Liquiritin (LQ) on GCE modified by N, S-LC/f-MWCNTs binary nanocomposite was investigated via differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The interpeak potential difference between LicA and LQ were 0.48 V. The calibration curves for LicA and LQ were obtained in the range of 0.4–70.0 μM and 0.1–150.0 μM, respectively, and the detection limits are 33 and 25 nM (S/N=3), respectively. The modified electrode has been successfully applied to the simultaneous determination of LicA and LQ in licorice with satisfactory recoveries as confirmed by HPLC method.

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