Electrospun Poly(Ethylene Oxide) Fibers Reinforced with Poly (Vinylpyrrolidone) Polymer and Cellulose Nanocrystals

Green poly(ethylene oxide) (PEO)/cellulose nanocrystals (CNCs)/poly(vinylpyrrolidone) (PVP) composites were prepared via electrospinning technique. The use of PVP and/or CNCs improved the overall thermal stability and mechanical properties of the PEO fibers. A strong synergistic reinforcing effect was achieved when PVP polymer and CNCs were combined in the composite. This synergistic reinforcement was accompanied with the formation of unique fiber-bead-fiber morphology. The beads were elongated and orientated along the applied force direction during tensile testing, providing an energy dissipation mechanism and a positive reinforcement effect. The combination of CNCs with PVP induced special chemical interactions, and distracted the interactions between PVP and PEO. As a result, the crystallinity of PEO was increased in the system, which also helped enhance fiber properties. The approach developed in this work offers a new way for reinforcing electrospun PEO-based composite fibers for sustainable green composite development

Cascade conversion of furfural to fuel bioadditive ethyl levulinate over bifunctional zirconium-based catalysts

Abstract(#br)Biomass-derived ethyl levulinate (EL) is currently deemed as a promising fuel bioadditive to improve (bio)diesel combustion performance without the sacrifice of its octane number. In this contribution, a range of Zr–Al bimetallic catalysts were prepared for the cascade conversion of furfural to EL by the integration of transfer hydrogenation and ethanolysis in ethanol. The ratio of Lewis to Brønsted acid sites (L/B) could be tuned by the ratio of Al 2 O 3 to ZrO 2 over SBA-15 support. Among these catalysts, Zr–Al/SBA-15(30:10) with appropriate L/B ratio of 2.25 exhibited an outstanding catalytic performance to give a furfural (FF) conversion up to 92.8% with a EL selectivity as high as 71.4% at 453 K in 3 h

Life cycle assessment of energy consumption and environmental emissions for cornstalk-based ethyl levulinate

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.This study analysed the sustainability of fuel-ethyl levulinate (EL) production along with furfural, as a by-product, from cornstalk in China. A life cycle assessment (LCA) was conducted using the SimaPro software to evaluate the energy consumption (EC), greenhouse gas (GHG) and criteria emissions, from cornstalk growth to EL utilisation. The total life cycle EC was found to be 4.54MJ/MJ EL, of which 94.7% was biomass energy. EC in the EL production stage was the highest, accounting for 96.8% of total EC. Fossil EC in this stage was estimated to be 0.095 MJ/MJ, which also represents the highest fossil EC throughout the life cycle (39.5% of the total). The ratio of biomass to fossil EC over the life cycle was 17.9, indicating good utilisation of renewable energy in cornstalk-based EL production. The net life cycle GHG emissions were 96.6 g CO2-eq/MJ. The EL production stage demonstrated the highest GHG emissions, representing 53.4% of the total positive amount. Criteria emissions of carbon monoxide (CO) and particulates ≤ 10 um (PM10) showed negative values, of -3.15 and -0.72 g/MJ, respectively. Nitrogen oxides (NOx) and sulphur dioxide (SO2) emissions showed positive values of 0.33 and 0.28 g/MJ, respectively, mainly arising from the EL production stage. According to the sensitivity analysis, increasing or removing the cornstalk revenue in the LCA leads to an increase or decrease in the EC and environmental emissions while burning cornstalk directly in the field results in large increases in emissions of NMVOC, CO, NOx and PM10 but decreases in fossil EC, and SO2 and GHG emissions.This study was supported by the National Natural Science Foundation of China (51506049), the National High Technology Research and Development Program of China (863 Program) (2012AA051802) and the Henan Province Foundation and Advanced Technology Research Project (132300413218)

Subjective Social Class and the Retention Intentions of Teachers from the Publicly Funded Normal Students Program in China: The Dual Mediating Effect of Organizational and Professional Identity

A stable teaching force is an important guarantee for the sustainable development of education. Teacher turnover is one of the reasons for the teacher shortage in rural areas. Although studies have examined the influencing factors of teachers’ turnover intention, little is known about the effect of subjective social status on teachers’ turnover intention, especially for publicly funded normal students program (PFNSP) teachers who play a vital role in improving the quality of education in less developed regions of central and western China. A questionnaire survey was conducted, which returned a total of 16,731 responses (8141 public recruited teachers and 1498 teachers from PFNSP). The study explores the influence of subjective social class on PFNSP teachers’ retention intention and the mediating role of organizational and professional identity on this impact. Except for organizational identity, the subjective social class, professional identity, and retention intentions of PFNSP teachers were significantly lower than those of publicly recruited teachers. There was a significant association between subjective social class and retention intentions of PFNSP teachers. In addition, organizational identity and professional identity had a significant positive relationship to PFNSP teachers’ retention intention, and played partial mediating roles in the relationship between subjective social class and retention intentions

Recent advances in Dirac spin-gapless semiconductors

Spin-gapless semiconductors (SGSs), the new generation of spintronic materials, have received increasing attention recently owing to their various attractive properties such as fully spin-polarization and high carrier mobility. Based on their unique band structures, SGSs can be divided into two types: parabolic and Dirac-like linear. The linear-type SGSs, also called Dirac SGSs (DSGSs), have real massless fermions and dissipation-less transport properties, and thus are regarded as promising material candidates for applications in ultra-fast and ultra-low-power spintronic devices. DSGSs can be further classified into p-state type or d-state type depending on the degree of contribution of either the p-orbitals or d-orbitals to the Dirac states. Considering the importance of the research field and to cover its fast development, we reviewed the advances in DSGSs and proposed our own viewpoints. First, we introduced the computational algorithms of SGSs. Second, we found that the boundaries between DSGSs and Dirac half-metals were frequently blurred. Therefore, a simple classification is proposed in this work. Third, we collected almost all the studies on DSGSs published in the past six years. Finally, we proposed new guidance to search for DSGSs among 3D bulk materials on the basis of our latest results

Subjective Social Class and the Retention Intentions of Teachers from the Publicly Funded Normal Students Program in China: The Dual Mediating Effect of Organizational and Professional Identity

A stable teaching force is an important guarantee for the sustainable development of education. Teacher turnover is one of the reasons for the teacher shortage in rural areas. Although studies have examined the influencing factors of teachers’ turnover intention, little is known about the effect of subjective social status on teachers’ turnover intention, especially for publicly funded normal students program (PFNSP) teachers who play a vital role in improving the quality of education in less developed regions of central and western China. A questionnaire survey was conducted, which returned a total of 16,731 responses (8141 public recruited teachers and 1498 teachers from PFNSP). The study explores the influence of subjective social class on PFNSP teachers’ retention intention and the mediating role of organizational and professional identity on this impact. Except for organizational identity, the subjective social class, professional identity, and retention intentions of PFNSP teachers were significantly lower than those of publicly recruited teachers. There was a significant association between subjective social class and retention intentions of PFNSP teachers. In addition, organizational identity and professional identity had a significant positive relationship to PFNSP teachers’ retention intention, and played partial mediating roles in the relationship between subjective social class and retention intentions

Perovskite R3c phase AgCuF3: multiple Dirac cones, 100% spin polarization and its thermodynamic properties

Very recently, experimentally synthesized R3c phase LaCuO3 was studied by Zhang, Jiao, Kou, Liao & Du [J. Mater. Chem. C (2018), 6, 6132-6137], and they found that this material exhibits multiple Dirac cones in its non-spin-polarized electronic structure. Motivated by this study, the focus here is on a new R3c phase material, AgCuF3, which has a combination of multiple Dirac cones and 100% spin polarization properties. Compared to the non-spin-polarized system LaCuO3, the spin-polarized Dirac behavior in AgCuF3 is intrinsic. The effects of on-site Coulomb interaction, uniform strain and spin-orbit coupling were added to examine the stability of its multiple Dirac cones and half-metallic behavior. Moreover, the thermodynamic properties under different temperatures and pressures were investigated, including the normalized volume, thermal volume expansion coefficient, heat capacity at constant volume and Debye temperature. The thermal stability and the phase stability of this material were also studied via ab initio molecular dynamic simulations and the formation energy of the material, respectively

Search for a new member of parabolic-like spin-gapless semiconductors: The case of diamond-like quaternary compound CuMn2InSe4

Spin-gapless semiconductors (SGSs) can be viewed as a potential upcoming candidate for spintronic applications, which bridge semiconductors and half-metallic materials (HMMs). In general, one of the spin directions is semiconducting while the other has a zero band gap. Until now, the concrete theory of SGS systems has not been developed and proved. There are limited investigations on the design of the theory of SGS systems and the availability of experimental data is very few. In this paper, a new possible candidate for parabolic-type SGS has been proposed in diamond-like quaternary compound, CuMn2InS4. Moreover, this compound has already been prepared and we hope the magneto-transport properties can be measured at low temperature to confirm its SGS behavior from experiment. Keywords: Spin-gapless semiconductors, Electronic structure, Magnetis