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1.
Silicon - Feeling prone to stress differs with plant production stage, water scarcity near commencement of grain filling phase has a significant reduced grain yield through fewer endosperm and sink...  相似文献   
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Water Resources Management - Drought is recurrently occurring in many parts of the globe. In contrast to other natural hazards, drought has complex climatic characteristics. Several environmental...  相似文献   
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Polyoxymethylene dimethyl ethers (PODEn) are extremely effective diesel additives to reduce soot formation during combustion. We introduce a series of Fe-Zn composite solid acid catalysts (SO42−/xFe2O3-yZnO), for the condensation reaction of methanol and paraformaldehyde (PF) with a cheap and feasible route to efficiently synthesize PODEn. These catalysts were characterized by different characterization techniques, namely BET, XRD, SEM, EDS, FTIR, and NH3-TPD and the results showed that Fe/Zn molar ratios strongly influenced the physicochemical characteristics of catalysts, thus affecting the methanol conversion and PODE1-6 and PODE3-6 selectivity. Accordingly, the methanol conversion was decreased and the selectivity of PODE3-6 was increased after increasing the Zn molar content. Comparatively, SO42−/Fe2O3-2ZnO exhibited superior catalytic activity among the various investigated catalysts due to the high acid density of strong acid sites. The optimal reaction conditions were observed to be at a 3.0 wt% catalyst loading (catalyst/reactant mass ratio), 2.5 hours ours of reaction time, a reaction temperature of 403 K, and a molar ratio of 3:1 of CH2O to methanol, achieving a high selectivity of 99.09% PODE1-6 and 28.23% PODE3-6 with 55.16% methanol conversion during the reaction.  相似文献   
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In the current study, graphene oxide (GO) was prepared using green chemistry with modified Hummer's method without incorporating sodium nitrate (NaNO3). Solvent casting was employed to fabricate GO-doped poly(ethylene oxide) (PEO), that is, PEO/GO composites with various proportion of Na2SO4 and were then subjected to characterization via advanced spectroscopic techniques for different physicochemical aspects to estimate their potential applications as marketable products. XRD analysis explored that fabricated composites are more crystalline than neat PEO. PEO/GO/Na2SO4 composite films offered maximum crystallinity. SEM displayed the same trend. TG/DTA thermogram exposed better thermal stability than pristine polymer. FTIR studies confirmed complexation among hybrid's components. Elongation-at-break and Young's modulus displayed an enhancing behavior with an incremental loading of salt and filler. In terms of mechanical performance, composite of PEO with 0.37 wt % GO and 0.08 g salt was found to be an ideal composition during the course of study. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48376.  相似文献   
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Theoretical Foundations of Chemical Engineering - In this study, the simulations for first-order chemical reactions (constructive and destructive) in the flow of the Casson fluid with...  相似文献   
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Wireless Networks - This research article presents an innovative approach based on analog network coding (ANC) in conjunction with space time block coding (STBC) which is termed as space time...  相似文献   
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Applied Intelligence - The genome of the novel coronavirus (COVID-19) disease was first sequenced in January 2020, approximately a month after its emergence in Wuhan, capital of Hubei province,...  相似文献   
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This article considers the dispersion of hybrid and mono nanoparticles in a fluid with viscosity (Williamson) dependent on shear rate, over a heated surface moving with nonuniform velocity and exposed to a magnetic field in the presence of an applied current. Extensive modeling leads to complex coupled mathematical models that are solved numerically via the finite element method (FEM). Convergent simulations are run to investigate the role of parameters on the dynamics of flow fields. The magnetic field intensity plays a role in controlling the magnetohydrodynamic boundary layer thickness (BLT) and thermal radiation controls the thickness of thermal boundary layers (TBL). However, the magnetic field intensity is responsible for an increase in BLT. In contrast to this, thermal radiation plays a role in controlling the thickness of the TBL. The impact of shear rate dependent viscosity on velocity is remarkable for both fluids. The motion of both of the fluids slows down when viscosity varies as a function of shear rate. Viscosity depending on the shear rate has a significant impact on wall shear stress. It is observed from simulations that wall shear increases when the parameters appearing in the model for shear rate dependent viscosity are increased. However, this increase in wall shear stress associated with a hybrid nanofluid is greater than the increase in wall shear stress associated with a mono nanofluid.  相似文献   
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