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A facile method is proposed in this work to prepare a carbon paper (CP) with outstanding properties by doping boron to catalyze graphitization at lower temperature. Boron was introduced into CP by impregnating carbon fiber preform into a boron/phenolic resin/ethanol solution, and then CP was obtained after the consecutive procedures of hot pressing, carbonization, and graphitization. Morphology, microstructure, composition, and physical properties of the doped and undoped CPs were thoroughly investigated via various techniques to exam the effects of boron concentration and graphitization temperature. Furthermore, the boron doped CP was fabricated into fuel cell gas diffusion layer (GDL) and membrane electrode assembly (MEA) to evaluate its performance through the single cell performance. The findings indicated CP doping with 2 wt% boron could lower the graphitization temperature by at least 200 °C. The B-doped GDL had a higher power density in comparison with the undoped GDLs made in our lab or from the commercial brands. • The innovative preparation method for carbon paper with high conductivity. • The effect of boron concentration and graphitization temperature on carbon paper. • The single cell performance of B-doped gas diffusion layer. [ABSTRACT FROM AUTHOR]

Brucellosis is a zoonotic disease that affects wild and domestic animals. It is caused by members of the bacterial genus Brucella. Guanylate-binding protein 1 (GBP1) is associated with microbial infections. However, the role of GBP1 during Brucella infection remains unclear. This investigation aimed to identify the association of GBP1 with brucellosis. Results showed that Brucella infection induced GBP1 upregulation in RAW 264.7 murine macrophages. Small interfering GBP1 targeting RNAs were utilized to explore how GBP1 regulates the survival of Brucella intracellularly. Results revealed that GBP1 knockdown promoted Brucella 's survival ability, activated Nod-like receptor (NLR) containing a pyrin domain 3 (NLRP3) and absent in melanoma 2 (AIM2) inflammatory corpuscles, and induced pro-inflammatory cytokines IFN-γ and IL-1β. Furthermore, Brucella stimulated the expression of GBP1 in bone marrow-derived macrophages (BMDMs) and mice. During the inhibition of GBP1 in BMDMs, the intracellular growth of Brucella increased. In comparison, GBP1 downregulation enhanced the accumulation of Brucella -induced reactive oxygen species (ROS) in macrophages. Overall, the data indicate a significant role of GBP1 in regulating brucellosis and suggest the function underlying its suppressive effect on the survival and growth of Brucella intracellularly. • B. melitensis infection increased GBP1 expression in RAW 264.7 murine macrophages. • Knocking down the expression of GBP1 promotes Brucella infection RAW 264.7 murine macrophages. • Knocking down the expression of GBP1 induces the production of inflammatory cytokine in Brucella -infected macrophages. • Knocking down the expression of GBP1 promotes B. abortus persistence in bone marrow-derived macrophages. • Brucella infection increased GBP1 expression in vivo. [ABSTRACT FROM AUTHOR]

Spatial analyses of traffic crashes have drawn much interest due to the nature of the spatial dependence and spatial heterogeneity in the crash data. This study makes the best of Geographically Weighted Random Forest (GW-RF) model to explore the local associations between crash frequency and various influencing factors in the US, including road network attributes, socio-economic characteristics, and land use factors collected from multiple data sources. Special emphasis is put on modeling the spatial heterogeneity in the effects of a factor on crash frequency in different geographical areas in a data-driven way. The GW-RF model outperforms global models (e.g. Random Forest) and conventional geographically weighted regression, demonstrating superior predictive accuracy and elucidating spatial variations. The GW-RF model reveals spatial distinctions in the effects of certain factors on crash frequency. For example, the importance of intersection density varies significantly across regions, with high significance in the southern and northeastern areas. Low-grade road density emerges as influential in specific cities. The findings highlight the significance of different factors in influencing crash frequency across zones. Road network factors, particularly intersection density, exhibit high importance universally, while socioeconomic variables demonstrate moderate effects. Interestingly, land use variables show relatively lower importance. The outcomes could help to allocate resources and implement tailored interventions to reduce the likelihood of crashes. • Geographically weighted modeling with local Random Forest models. • Local associations between crash frequency and various factors in the USA. • Modeling and analyzing nonlinear effects of factors. • Revealing spatially distinctive effects of factors on crash frequency. [ABSTRACT FROM AUTHOR]

Age-related hearing loss (ARHL) is a common neurodegenerative disease. Its molecular mechanisms have not been fully elucidated. In the present study, we obtained differential mRNA expression in the cochlea of 2-month-old miR-29a +/+ mice and miR-29a −/− mice by RNA-seq. Gene ontology (GO) analysis was used to identify molecular functions associated with hearing in miR-29a −/− mice, including being actin binding (GO: 0003779) and immune processes. We focused on the intersection of differential genes, miR-29a target genes and the sensory perception of sound (GO:0007605) genes, with six mRNA at this intersection, and we selected Col1a1 as our target gene. We validated Col1a1 as the direct target of miR-29a by molecular and cellular experiments. Total 6 pathways involved in Col1a1 were identified by through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. We selected the focal adhesion pathway as our target pathway based. Their expression levels in miR-29a −/− mice were verified by qRT-PCR and Western blot. Compared with miR-29a +/+ mice, the expression levels of Col1a1 , Itga4 , Itga2 , Itgb3 , Itgb7 , Pik3r3 and Ptk2 were different in miR-29a −/− mice. Immunofluorescence was used to locate genes in the cochlea. Col1a1 , Itga4 and Itgb3 were differentially expressed in the basilar membranes and stria vascularis and spiral ganglion neurons compared to miR-29a +/+ mice. Pik3r3 and Ptk2 were differentially expressed in the basilar membranes and stria vascularis, but not at the s spiral ganglion neurons compared to miR-29a +/+ mice. Our results show that when miR-29a is knocked out, the Col1a1 mediates the focal adhesion pathway may affect the hearing of miR-29a −/− mice. These findings may provide a new direction for effective treatment of age-related hearing loss. • Age-related hearing loss miR-29a mouse model by RNA-seq analysis. • MiR-29a deletion leads to up-regulation of Col1a1 expression, which results in decreased hearing in mice. • Col1a1 is affecting hearing through the focal adhesion pathway. [ABSTRACT FROM AUTHOR]

• Experimental study on inhibition of gas hydrate formation for CO 2 separation. • Develop a chemical affinity model to predict CO 2 hydrate formation. • Optimal inhibitory compound system is 15 mg/mL glucose + 1.00 mg/ml attapulgite. • Induction time of hydrate formation is extended by approximately 122% • Gas consumption is reduced by 23.72% to improve the inhibitory effect. Natural gas and water can form complex cage crystals in oil and gas pipelines under certain conditions. The natural gas hydrate formed after crystal clustering can block the pipeline and affect the operation efficiency of the pipeline, and even cause equipment damage, bringing economic and security problems to enterprises. In the present study, we experimentally investigated the inhibition of CO 2 formation hydrate using attapulgite (ATP) and glucose (GLC). The kinetic influence on the formation of CO 2 hydrate by the complex pairing of kinetic inhibitor ATP is conducted under the working conditions of 277.15 K and 3.5 MPa. The effect of compound inhibitors on the temperature and pressure conditions, growth process and gas consumption of hydrate formation are revealed. The chemical affinity model of CO 2 hydrate formation under a compound inhibitor system is derived and established based on experimental studies. The results show that the combination of GLC and ATP can inhibit the formation of CO 2 hydrate to varying degrees, prolong the induction time of hydrate, and reduce the consumption of CO 2. The optimized experimental studies demonstrate that the best inhibitory compound system is 15 mg/mL GLC + 1.00 mg/mL ATP. Compared with the pure water system and single 15 mg/mL GLC system, the induction time is extended by 122.61% and 122.23%, while the gas consumption is reduced by 23.72% and 3.41%. The results provide new ideas and methods for the prediction of hydrate formation in the compound inhibitor system for the safe operation of oil and gas pipelines. [ABSTRACT FROM AUTHOR]

The low hydraulic efficiency of the pump as turbine (PAT) poses a major challenge to the runner design. This paper introduces a new strategy for designing and optimizing the performance of PAT runner. The strategy process is mainly divided into four steps, namely blade parametric design, significance evaluation of parameters, construction of optimizing surrogate model and optimization of improved PSO algorithm. Compared with the current design methodologies, not only does this optimization strategy propose the system design and optimization process, but also it breaks down the process into well-defined steps and simplifies them. The hydraulic efficiency of PAT optimized by this optimization strategy reaches 84.76%, which improves 3.93%. A test bench has been built to test the optimizing strategy. The maximum difference of experimental data is 1.5%, which meets the requirements of practical engineering application, and verifies the reliability of the optimization strategy process. The optimizing strategy process can be extended to apply to pump, fan, conventional turbine and other blade fluid models, and it can be further extended to apply to the optimization design of 3D blades with a high specific speed. [Display omitted] [ABSTRACT FROM AUTHOR]

• The 2308Δ gntR ghost is non-toxic in mice. • The 2308Δ gntR ghost can elicit an anti- Brucella -specific IgG response. • 2308Δ gntR ghost immunizations induce a cellular response. • 2308Δ gntR ghost induces protection against B. abortus challenge. • 2308Δ gntR ghost can enhance splenic T lymphocyte activity. Brucellosis, which is caused by Brucella spp., is an important zoonotic infectious disease that can cause great hazard to public health and safety. However, the current vaccines have several drawbacks, including residual virulence for animals and humans. Bacterial ghost is the empty envelopes of bacteria, which emerge as a proper vaccine candidate. With the purpose of generating B. abortus ghosts and investigating the immunogenicity of bacterial ghosts as vaccine candidate, we used homologous recombination and bacterial ghost technologies to construct 2308Δ gntR ghost strain. Mice were injected with 2308Δ gntR ghost and the safety and immunogenicity of ghost were further evaluated. The mice inoculated with ghost showed no splenomegaly. The 2308Δ gntR ghost induced high protective immunity in BALB/c mice against challenge with S2308, and elicited an anti- Brucella -specific immunoglobulin G (IgG) response and induced the secretion of interferon gamma (IFN-γ) and interleukin-4 (IL-4). Additionally, 2308Δ gntR ghost demonstrated strong spleen CD4+ and CD8+ T cell responses. These results suggest that 2308Δ gntR ghost is a potential vaccine candidate and may represent a promising new approach for vaccination against Brucella infection. [ABSTRACT FROM AUTHOR]

• Performability of dynamic multi-state k -out-of- n : G systems is studied. • A novel and fast analytical modeling method is proposed. • A smart home lighting control system is analyzed. • Correctness is verified using a case study of an oil supply system. • Efficiency is verified using comprehensive empirical and comparative studies. A dynamic multi-state k -out-of- n : G system, denoted by DMS(k, n , G) is a system where the system and its components exhibit multiple performance levels, and the system has different requirements on the number of working components in different states. DMS(k, n , G) abounds in both industrial and military applications. In this paper, a novel and efficient analytical method based on multi-valued decision diagrams (MDDs) is proposed for performability assessment of DMS(k, n , G) with non-identical components. Unlike existing approaches where multiple combination operations between models of lower performance levels are needed for constructing the model of a higher performance level, the proposed MDD generation algorithm constructs the system performability MDD in a top-down manner by considering multiple system state requirements simultaneously. A smart home lighting control system is analyzed to demonstrate the application of the proposed method. A detailed case study of an oil supply system is provided to verify the correctness of the proposed method and illustrate component sensitivity analysis. Complexity analysis and comprehensive empirical studies are performed to demonstrate that the efficiency of the proposed model construction is greatly improved as compared to the existing method, enabling fast model generation and efficient analysis of large-scale DMS(k, n , G). [ABSTRACT FROM AUTHOR]

GntR10 is a transcriptional regulator in Brucella. Nuclear factor-kappa B (NF-κB) is involved in many cellular activities, playing major roles in orchestrating the expression of inflammatory genes and regulating protein function that is essential for pathogenic bacteria during infection. GntR10 deletion was previously found to affect the growth and the virulence of Brucella and expression levels of target genes of GntR10 in mice. However, the mechanisms of affection of NF-κB regulated by Brucella GntR10 are still unclear. Here, GntR10 deletion could regulate the expression of LuxR-type transcriptional activators (VjbR and BlxR) of the quorum sensing system (QSS) and type IV secretion system (T4SS) effectors (BspE and BspF) of Brucella. It could further inhibit the activation of the regulator NF-κB and affect the virulence of Brucella. This research provides new insights into the designing of Brucella vaccines and the screening of drug targets. Transcriptional regulators are predominant bacterial signal transduction factors. The pathogenicity of Brucella is due to its ability to regulate the expression of virulence related genes including quorum sensing system (QSS) and type IV secretion system (T4SS). Transcriptional regulators are designed to regulate gene expression and enact an appropriate adaptive physiological response. Here, we show that Brucella transcriptional regulator GntR10 regulated the expression of QSS and T4SS effectors, which affected the activation of NF-κB. [Display omitted] • 1558 proteins with quantitative information were identified from S2308 and 2308Δ gntR10. • The expression of T4SS virB1 was reduced in 2308Δ gntR10. • Expressions of VjbR and BlxR of QSS were down-regulated. • The activation of regulator NF-κB was inhibited in 2308Δ gntR10. [ABSTRACT FROM AUTHOR]

Abstract Six polyimides, containing pyridine and spirocyclic units, were successfully synthesized by chemical imidization. Structure-dependent properties such as thermal decomposition temperatures and gas permeabilities of the high-performance polymers were explicitly investigated. Results showed that all polyimide films exhibited good solubility in common organic solvents and non-polar solvents such as chloroform and tetrahydrofuran. The polymers exhibited good thermal stability, all demonstrating thermal decomposition temperatures (T d10%) over 496 °C in nitrogen. Important from a commercial viewpoint, the permeability coefficients of these for the acidic gas CO 2 showed an increase over other tested gases by virtue of the basic group pyridine (C–N linkages) in their structures. Graphical abstract Image 1 Highlights • Polyimides exhibited good solubility, which is easily to cast into film and apply in practice. • Polymers exhibited good thermal stability which maintain their structural integrity below 450 °C. • The permeability coefficients of CO 2 increased significantly by introduction of the pyridine groups. • Demonstrated the importance of introducing the rigidity to the chains for improving gas separation performance. [ABSTRACT FROM AUTHOR]

Abstract Hydropower development involves managing a network of diverse stakeholders. Owners play a critical part in effectively cooperating and establishing inter-organizational linking with stakeholders to achieve multiple project objectives. According to the data which is from the construction industry of hydropower in China, the research aims to investigate the causal relationships between cooperation with stakeholders and inter-organizational linking systematically, together with their impacts on the owners' social capital by developing and testing a conceptual model. Path analysis confirms that cooperation with stakeholders cannot only directly improve owners' social capital but also exert its influence on social capital through enhancement of inter-organizational linking, thereby improving project performance and winning external supports for owners' long-term development. Social network analysis shows that, from the perspective of owners, project stakeholders are clearly grouped into four clusters related to project feasibility, implementation, procurement and resettlement of migrants. These clusters reflect stakeholder's different roles and connections with each other in hydropower development. Understanding the above in-depth underlying relationships is fundamental for improving multi-organizational dynamics research to a state of the art, and help project participants to appropriately adopt cooperative strategies for maximizing the effectiveness of each stakeholder's resources. Highlights • Hydropower development involves managing a network of diverse stakeholders, in which owners play a key role. • Cooperation with stakeholders can improve owners' social capital diectly and through inter-organizational linking. • Hydropower project stakeholders are grouped into four clusters: project feasibility, implementation, procurement and migrants. • Suppliers distribute separately from other stakeholders, requiring the owners to build supplier networks to buy stable products. • Local residents have the lowest centrality in the network, showing owners should take measures for migrants' sustainable development. [ABSTRACT FROM AUTHOR]

Grassland ecosystems are sensitive to invasions by plants from other functional groups which can alter soil greenhouse gas (GHG) fluxes. However, the effects of plant invasion on net GHG exchanges between soils and the atmosphere, plant production, and global warming potential (GWP) of annual grasslands is poorly understood. To evaluate the impacts of perennial forb invasions on GHG budgets of an annual grassland in China, we measured soil carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) fluxes over two years in replicated invaded (dominated by Alternanthera philoxeroides or Solidago canadensis ) and non-invaded (dominated by the annual grass Eragrostis pilosa or the annual forb Sesbania cannabina ) field sites. On average, soil CO 2 and N 2 O emissions from invaded sites were 30% and 76% higher, respectively, relative to sites dominated by native species. Emissions of N 2 O and CO 2 were especially high in Solidago and Alternanthera dominated sites, respectively. Soil CH 4 emissions did not vary with plant species. On average, total biomass C of invaded sites was higher than that of the native dominated sites but this reflected the high C in Solidago dominated sites. Global warming potential (GWP) was increased by Alternanthera invasions and decreased by Solidago invasions. Plant invasions affected GWP of these annual grasslands through higher emissions of some GHGs but also sometimes higher biomass C. Together, this suggests that perennial forb invasions could change the net source or sink role of annual grasslands for GHG budgets, but the effects on GWP vary among species depending on GHG responses and C storage. [ABSTRACT FROM AUTHOR]

Background Comparing to SPECT and MRI, with higher temporal and spatial resolution and development of radiation dose reduction, myocardial computed tomography perfusion has emerged as a potential method for evaluation of hemodynamic myocardial ischemia. This meta-analysis systematically analyzed the performance of dynamic CT myocardial perfusion (DCTMP) to diagnose myocardial ischemia (MI) with clinically established reference methods [MR/SPECT/PET perfusion and fractional flow reserve (FFR)] as the reference standard. Methods We searched PubMed, Embase and web of science databases for all published studies that evaluated the accuracy of DCTMP to diagnose MI met our inclusion criteria. An exact binomial rendition of the bivariate mixed-effects regression model with test type as a random-effects covariate was performed to synthesize the available data. Results The search revealed 13 eligible studies including 482 patients. The pooled sensitivity and specificity of myocardial blood flow (MBF) were 0.83 (95% CI: 0.80 to 0.86) and 0.90 (95% CI: 0.88 to 0.91) at the segment level, 0.85 (95% CI: 0.80 to 0.88) and 0.81 (95% CI: 0.78 to 0.84) at the artery level, and 0.93 (95% CI: 0.82 to 0.98) and 0.82 (95% CI: 0.70 to 0.91), at the patient level, respectively. The high area under the sROC curves of MBF were 0.944 at segment level, 0.911 at vessel level and 0.949 at patient level, respectively. Conclusions DCTMP has a high diagnostic accuracy in detecting myocardial ischemia and it may increase significantly at segment level in combined use of coronary CTA. [ABSTRACT FROM AUTHOR]

Split-flow is a fundamental manipulation method for liquid transport, which is challenging in microfluidics by simple structures, owing to the distinct flow mechanism in microchannels. Herein, we present a new strategy for fabricating switch-alternative fluid-splitters by reasonably embedding obstacle microstructures in microchannels. Precise confinement of triple-phase (gas, fluid front, obstacle microstructure) contact line of fluid fronts on the microstructures provides the device with advantage in controlling the flow motion of fluid in microchannels. The microstructures could act as a burst microvalve, and duration of fluid front flowing through the microvalve is essentially controlled by the quantity of the obstacles. Based on appropriate arrangement of the obstacles, we demonstrate that fluid-splitters with four and eight flow states of water and blood in microchannels could be obtained. In particular, implementation of the fluid splitters mostly relies on the regulation of the triple-phase contact line, which simplifies the complex equipments and enhances the compatibility of the devices. It is believed that the fabrication strategy of the switch-alternative fluid-splitters can be extensively used for disposable manipulation of fluid in microfluidic networks. [ABSTRACT FROM AUTHOR]

An electric aircraft propulsion system utilizes a high efficiency motor to generate thrust for electric aircraft. However, it can be challenging to maintain high efficiency for the fixed pitch propeller, which is commonly used in electric aircraft, through all phases of the flight. This paper investigates the power demands of the electric aircraft during the climb and the cruise phases according to the flight profile, and presents a model to estimate the energy consumption per flight. Simulation results suggest that the efficiency in the climb and the cruise phases can affect the energy consumption of an electric aircraft. Efficiency during the climb phase can have a significant effect on the capacity of the electric aircraft propulsion system. Based on the aforementioned results, this paper proposes a novel approach to achieve high efficiency, in which the optimal efficiency points of the electric aircraft propulsion system in the climb and the cruise phases can be obtained by solving an optimization problem with minimizing the energy consumption per flight as the object function and under the constraints that the climb and cruise phases must be successful. For testing purposes, the proposed method is adopted to the design of the electric aircraft propulsion system on a specific two-seater electric aircraft. Experimental results obtained from real flights suggest that the proposed method can reduce the energy consumption of the electric aircraft by over 10%, while reducing the capacity demand for the electric aircraft propulsion system. [ABSTRACT FROM AUTHOR]

Partially premixed combustion using gasoline-like fuels on compression ignition engines shows great potentials to break the soot-nitrogen oxides trade off and reduce both emissions simultaneously. By simply adjusting the dilution strategies and injection events, the control of partially premixed combustion is relatively easier compared to other low-temperature combustion concepts. However despite these advantages, recent research shows this concept tends to emit ultra-fine particles. Most previous work on partially premixed combustion only focuses on the soot emissions while the particulate matter in terms of number concentration and size distribution are not well investigated. Ultra-fine particles are dangerous to human health and are getting increasing attentions. Thus the detailed particulate matter emission from partially premixed combustion needs to be further investigated. In this work four gasoline-like ternary fuel blends are designed and experimentally tested under partially premixed combustion. The test blends all share the same two base fuels and blended with different additives. The fuel composition is varied to have the same research octane number. Tests are conducted under different engine loads and dilution strategies since the temperature and oxygen concentration are the key factors in the formation and oxidation of soot. Standard diesel is also tested under the same conditions as a comparison. It is found that these blends are capable of running under partially premixed combustion at low and medium loads and they produce near zero soot emissions when using high exhaust gas recirculation rate. However, these blends do emit smaller particles than diesel under all test loads. Besides, blends with oxygen content yield less soot emissions and smaller particles compared to non-oxygen blends. [ABSTRACT FROM AUTHOR]

Catalytic activity improvement by Pd-based catalyst for methanol oxidation is significant to the development of alkaline direct methanol fuel cells. Herein, we demonstrate the performance of methanol oxidation on Pd catalyst could be greatly increased by Y 2 O 3 . The promotion effect is discussed with the help of physical and electrochemical characterization techniques by comparing with a home-made Pd/C catalyst in the identical condition. The presence of Y 2 O 3 in the system is well confirmed by the characteristic peaks indicated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy(XPS); and a strong electronic effect between the Pd and Y 2 O 3 is reflected by an evident shift of binding energy to the lower direction as shown in the XPS spectrum. The catalytic activity expressed by current density reveled by cyclic voltammetry is about 145 mA cm −2 , 1.5 times higher than that of the reference catalyst; current retaining ability of 5 times higher than that of the reference catalyst is revealed by Chronoamperometry. Higher catalytic activity and stability for methanol oxidation is discussed due to the relatively well dispersed Pd particle size, increased electroactive surface area and the synergistic interaction of Pd and Y 2 O 3 . The work demonstrates the hybrid Pd Y 2 O 3 /C as a newly effective catalyst for alkaline direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon confined iron-nickel alloy/iron fluoride doped by oxygen derived from nano rod-like Fe 2 Ni MIL MOF. • Structural transformation demonstrated by spectroscopic analysis was correlated to electrochemical catalytic performance. • C/O-FeNi/FeF 2 exhibited high catalytic activity and stability for OER with faster charge transfer ability. • High activity comes from carbon confined active phase, increased polarity, strong electronic effect and efficient synergism. Carbon confined active phase plays a significant role in the novel catalyst materials development and fabrication. Herein, we demonstrate such a catalyst material in the form of carbon confined iron-nickel alloy/iron fluoride doped by oxygen (C/O-FeNi/FeF 2) derived from the Fe 2 Ni MIL MOF via facile carbonization and fluorination for efficient oxygen evolution reaction (OER) in the water-splitting reaction. The structural transformation from the Fe 2 Ni MIL MOF to the C/O-FeNi/FeF 2 is demonstrated by the spectroscopic analysis and correlated to their electrochemical catalytic performance. Because of some combined merits resulting from the carbon confined active phase, increased polarity, strong electronic effect and efficient synergism of metal and metal fluoride for the facile active phase reconstruction in this hybrid system, this catalyst exhibits many good characteristics for electrochemical measurements in terms of improved conductivity, high intrinsic activity and stability, fast catalytic kinetics, increase surface area and rapid charge transfer ability. Specifically, the C/O-FeNi/FeF 2 catalysts have a low overpotential of ca. 250 mV when loaded on a glass carbon electrode to offer the current density of 10 mA cm−2 in the alkaline electrolyte for OER; and no obvious performance decay is observed in the long-term stability test conducted at different potentials. The current results will be instructive for novel carbon confined catalyst and MOF derived catalyst design and fabrication in the energy catalysis reaction. [ABSTRACT FROM AUTHOR]

A series of aromatic polyimides were synthesized from three Cardo-based diamines, BAF, DDA, BAP, with different building blocks (ether linkage, dioxane linkage and C–C linkage), and commercially available dianhydride 6FDA. All polyimides were readily soluble in conventional aprotic and protic solvents, which guaranted the fabrication of self-standing membranes for gas separation applications. The Cardo-based polyimides also exhibited excellent thermal stability, with weight loss temperatures (T 5 %) of over 538 °C, and good mechanical properties, with tensile strength in the range of 41–64 MPa. Compared to 6FDA-BAF, the substitution of dioxane linkage for ether linkage resulted in increased chain rigidity, looser polymer chain packing, and larger fractional free volume. Consequently, as displayed by single gas permeation tests, 6FDA-DDA showed higher permeability coefficients without significantly sacrificing selectivity. In addition, the CO 2 permeability of 6FDA-BAP was around 2 times as high as that of 6FDA-BAF, while the CO 2 /CH 4 selectivity increased by 11%. This can be explained by the lower rotational mobility and the relatively higher imide content caused by the absence of the flexible ether linkage and dioxane linkage in polymer backbone. In short, fundamental insights into structure-property relationships of the Cardo-based polyimides observed in this study provided guidance for the molecular structure design of the gas separation membranes. [Display omitted] • Three Cardo-based polyimides containing different building blocks were successfully synthesized. • The effect of rigidity and microstructure on gas separation performance of the Cardo-based polyimides was elucidate. • The substitution of dioxane for ether linkage led to the increased chain rigidity and the looser chain packing. • The polyimide containing C–C linkage showed better combination of permeability and gas-pair selectivity. [ABSTRACT FROM AUTHOR]

This paper focuses on the development of a 3D/1D patched transient heat transfer model (called 3D/1D patched model). It is proposed for getting accurate thermal boundary conditions in investment castings. In the 3D/1D model, heat transfer in the mould is assumed to take place only in a direction perpendicular to the mould, called 1D heat transfer and is computed via the FD solution of a 1D heat transfer equation. To reduce computational cost and simplify the mesh generation, the coordinates of cell centre and the temperature in the mould can be calculated by the model instead of meshing mould. When 1D patched model is integrated into the 3D CFD code PHYSICA, An area is present where 3D/1D model cannot cover, called ‘dead corner’. To overcome the effect of ‘dead corner’, a patch is introduced to put on it. The simulation results show that the 3D/1D patched model improves the accuracy when calculating the heat transfer through the mould–casting interface. However, it does not function well in 3D geometrical model. [ABSTRACT FROM AUTHOR]

In this paper, we study the multiplicity of nontrivial solutions for asymptotically linear discrete problem by using critical point theory, Morse theory and minimax methods. We obtained that the problem has at least two nontrivial solutions under various conditions. [ABSTRACT FROM AUTHOR]

The gas diffusion substrate (GDS) is essential in the proton exchange membrane fuel cells. Its fabrication techniques affect the performance significantly and are worthy of investigation. In this study, a manufacturing process of the GDS is proposed to understand the formation process of GDS and promote its structure and performance more pertinently. Different states during the preparation process, raw carbon paper, pre-curing, curing, carbonation, and graphitization, are characterized and measured. Experimental and numerical methods are employed to determine the relationships between microstructure, transport, and mechanical performance variation with the fabricating processes. The results show that its porosity, average pore size, and effective diffusivity decrease first and increase after curing. These parameters after graphitization are lower than that of the carbon paper (CP). The electrical resistivity increases dramatically while pre-curing and decreases gradually after curing, carbonation, and graphitization, and it is much reduced after graphitization. Moreover, mechanical measurement results show that both the picks of tensile strength and flexural modulus occur after curing. Its tensile strength shows little change after graphitization compared to the initial paper's. In contrast, the flexural modulus is improved significantly. • Microstructural characteristics of GDS during fabrication are investigated. • Transport properties and pore-scale simulations for GDS are performed. • Precuring, curing, carbonation, and graphitization on properties are studied. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we study the existence of nontrivial solutions for a class of second-order difference equations with multiple resonance at both infinity and the origin by applying the critical point theory and Morse theory. [Copyright &y& Elsevier]

Abstract: In this paper, we study the existence of nontrivial solutions for a second order difference systems with multiple resonance at both infinity and zero by applying Morse theory. [Copyright &y& Elsevier]

• Freeze-drying/annealing approach induced phase structure tuning of Ni-NiO system. • Annealing temperature was significant to influence the Ni-NiO crystal structure. • Efficient Ni-NiO synergistic effect promoted the catalytic performance for urea oxidation. • Efficient kinetics and rapid charge transfer-ability were found for urea oxidation. The sluggish kinetics of urea electro-oxidation seriously limits its application in hydrogen production and wastewater treatment. Herein, we demonstrated an easy freeze-drying/annealing approach induced phase structure tuning of graphene supported Ni-NiO nanoparticles system for efficiently boosting urea oxidation performance. The annealing temperature was found significant to influence the Ni precursors decomposition, crystal structure formation and catalytic performance for urea oxidation. By increasing the temperature from 350 °C to 550 °C, more metallic Ni was formed in the Ni-NiO system, and because of the efficient Ni-NiO synergistic effect and conductivity improvement, the sample obtained at 450 °C exhibited the highest catalytic activity and stability for urea oxidation. Specifically, the current density at 0.5 V was 38.24 mA cm−2, about 5.6 and 30 times of the control sample of graphene supported NiO and Ni respectively. Efficient kinetics and rapid charge transfer-ability were also found for urea oxidation by a series of electro-kinetics analysis. The current work showed an easy way for Ni-based catalyst structure tuning with enhanced kinetics for urea oxidation, which is helpful for the sustainable utilization of urea molecular in electrochemical energy. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Shape memory polyimides (SMPIs) have gained considerable attention as smart deformation materials for their excellent properties. However, the relationship between shape memory performance and polyimide structure have hardly mentioned. Hence, three shape memory polyimides were manufactured with different structure monomers. Pyridine-contained polyimide (PI-1) and trifluoromethyl-contained polyimide (PI-3) were investigated by experimentally and molecular simulations on the physical properties and shape memory behaviors comparing with the benzene-structured polyimide (PI-2). Results showed that all polyimide films exhibited good thermal properties (T g DMA>258 °C). All PIs possessed great shape memory performances and stabilities. It was found that the introduction of pyridine group (PI-1) will restrict the tensile strain in dual-shape memory process of 155% but enhance the R f and R r of 99.7% and 93.7%, comparing with PI-2 of 256%, 99.8% and 89.2%, respective. Moreover, PI-3 with the presence of trifluoromethyl group can marked improve the elongation strain of 313%, in the meanwhile kindly reduce the R r of 88.4%. Additionally, fractional free volume and storage modulus under high temperature provided simultaneous support for different shape memory performances. The current research may have specified a new way for the production and usage of the smart materials in practice. Image 1 • Polyimides exhibited good thermal stability, which can apply in high temperature condition. • Polyimides based on different chain structures processed various shape memory effects. • Demonstrated the importance of structure-shape memory properties especially strain and shape memory recovery rate. [ABSTRACT FROM AUTHOR]

Four spirobichroman-based polyimides (6FDA-F, 6FDA-O, 6FDA-P, and 6FDA-M) were successfully obtained via polyreaction between diamines of different substituents (-H, -OCH 3 , -N, and -CH 3) and 4,4′-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA). The molecular weights, thermophysical, dihedral angle of the molecules, fractional free volume, d-spacing, Brunauer–Emmett–Teller surface area, and gas separation performance were studied through a combination of experiments and molecular dynamics simulations. These polymers show high molecular weights, with number-average molecular weights (M n) in the range of 5.0–15.3 × 104, and excellent thermal stability, with weight loss temperatures (T 5%) of over 420 °C. The pure-gas (O 2 , N 2 , CO 2 , and CH 4) permeation results indicated that the four polymers selectivity of CO 2 /CH 4 over 31 and that 6FDA-F had the highest gas permeability among the four tested gases. Importantly, the dihedral angle from molecular simulation was used to clarify the phenomenon wherein the 6FDA-P gas permeability lower than 6FDA-F. A detailed analysis indicates that -CH 3 increased the gas permeability of the polyimides, while the turnstile-like rotary thermal motion of -OCH 3 formed channel obstacles and improved the gas selectivity. The polymers containing pyridine ring and those containing benzene ring follows different gas separation mechanisms, based on the gas solution-diffusion behaviour. Unlabelled Image • Polyimides with substituent of benzene ring shown the best overall separation performance for CO 2 /CH 4 and O 2 /N 2. • Dihedral angle between adjacent plane used to insights into the mechanisms of gas permeability enhancement for polymer. • The -CH 3 increases gas permeability, while the -OCH3 forms channel obstacles and improves gas selectivity. • Polyimides containing pyridine ring and those containing benzene ring follows different gas separation mechanisms. [ABSTRACT FROM AUTHOR]

ISPM and ISNOx as a function of EGR rate. Bio-derived alcohol fuels and oxygenated aromatic hydrocarbons are interesting alternative fuels applicable in low temperature combustion concepts due to their low reactivity. In this paper, three oxygenated fuels are mixed with n-heptane respectively as binary fuel blends to investigate combustion and emission characteristics of the oxygenated fuels with different molecular structures. The n-butanol/n-heptane blend has an identical stoichiometric air/fuel ratio as benzaldehyde/n-heptane blend while anisole is used to assess the importance of the aromatic structure. Standard diesel is also used as a baseline fuel. Experiments are performed on a single-cylinder heavy-duty diesel engine at medium and high loads. It is found that the n-butanol/n-heptane blend presents a higher premixed burn fraction and a higher pressure rise rate at both loads. Increasing injection pressure leads to lower soot emissions and higher NO x emissions are found regardless of fuel type. The n-butanol/n-heptane blend achieves 0.027 g/kWh and 0.2 g/kWh for engine-out soot and NO x emissions with high exhaust gas recirculation rate at high load. For the benzaldehyde/n-heptane blend and diesel, the classical NO x /soot tradeoff is observed under the same operating conditions. The particle size distribution mainly shows accumulation mode particles increase at a high exhaust gas recirculation rate, irrespective of the fuel structure. Only the n-butanol/n-heptane blend emits more nucleation mode particles and much less accumulation mode particles compared to the benzaldehyde/n-heptane and anisole/n-heptane blends. Clearly, the fuel structure influences the soot formation and is therefore not fully determined by the stoichiometric air/fuel ratio of the base fuel. [ABSTRACT FROM AUTHOR]

Herein, a copper (II) ions - doped thin film composite (TFC-Cu) membrane with ridge-valley morphology was prepared by interfacial polymerization (IP) via incorporating copper (II) ions in the aqueous phase. The complexation of copper (II) ions with N atoms on m-phenylenediamine (MPD) affects the diffusion of MPD from the aqueous to the oil phase, leading to instability of the IP process and consequently the formation of ridge-valley morphology on the membrane surface. The ridge-valley morphology increases the contact area between the membrane and the solvent, which lays the foundation for increased solvent permeability. Moreover, the hydrophilicity and permeability of the composite membrane can be modulated by adjusting the content of copper (II) ions in the aqueous phase. The methanol permeation performance of the preferred TFC-Cu 100 membrane was 13.27 L m−2 h−1 bar−1, an improvement of 65.46% over the unmodified TFC membrane. Meanwhile, the TFC-Cu 100 membrane also showed a high retention level (98.82%) of RDB dye. In addition, the TFC-Cu 100 membrane maintained good long-term organic solvent nanofiltration (OSN) performance after 10 days of immersion in N, N-dimethylformamide (DMF) at 80 °C. This work offers attractive prospects for the modification of the IP process using other inorganic salts to optimize the OSN performance of the membrane. [Display omitted] • A copper (II) ions-doped TFC-Cu membrane with ridge-valley morphology was prepared by inorganic salt-modified IP. • Copper (II) ions-doped membrane showed the markedly enhanced solvent flux compared with TFC membrane. • The surface morphology and permeability can be modulated by controlling the copper (II) ions content. • The copper (II) ions-doped membranes have good long-term organic solvent nanofiltration performance in DMF. • The combination of copper (II) ions and the separation layer strategy provide a way to improve the OSN performance of TFC-Cu membranes. [ABSTRACT FROM AUTHOR]

The Volume of Fluid method and Re-Normalisation Group (RNG) k-ε turbulence model were employed to predict the gas-liquid two-phase flow in a terrain-inclined pipeline with deposited liquids. The simulation was carried out in a 22.5 m terrain-inclined pipeline with a 150 mm internal diameter. The flow parameters were numerically analyzed in detail including the phase distribution in pipes, the velocity and pressure around the elbow, the liquid flow rate and liquid holdup in different cross-section and the volume of liquid outflow. The numerical results presented that a wave crest formed on the liquid level under the suction force which caused by the negative pressure around the elbow, and then it touched to the top of the pipe. When the liquid blocked the pipe, the pressure drop between the upstream and downstream of the elbow increased with the increase of the gas velocity. At larger gas velocity, more liquid was carried out of the pipeline. The liquid periodically flowed and returned along the uphill section when the liquid was no longer flowing out of the pipeline. [ABSTRACT FROM AUTHOR]

Metal halide perovskite single crystal (SC) has attracted wide attentions in the field of photoelectric detection. All-inorganic perovskite SCs are much more stable than the hybrid counterparts, but its rapid fabrications usually end up low quality. We proposed a modified solvent-evaporation method that can rapidly obtain smooth and transparent high-quality CsPbBr 3 single crystal with a surface roughness of only 5 nm in a few hours. In this method, the lattice phase of the SC and the growth rate is precisely controlled by the solution temperature, which is raised to the narrow range above the cubic-to-tetragonal phase transition temperature. This precisely controlled solvent temperature allows the CsPbBr 3 SC growing immediately into cubic phase, and limits the volatilization rate of solvent, thus inhibiting the defect density. The SCs grown this way are of high crystallinity, as the half-height width of the (100) and (200) peaks of XRD rocking curve is 0.0154° and 0.0176°, respectively. Characterization of photoelectric properties shows great potential for applications in X-ray detection and photodetection. • CsPbBr 3 single crystals were grown by a modified evaporative solvent method. • The crystal quality is very high crystallinity as the half-height width of the rocking curve as low as 0.0176°. • The effect of growth temperature on crystal quality is investigated. • The growth time of large size (3 mm) CsPbBr 3 single crystals is reduced to 10 h. [ABSTRACT FROM AUTHOR]

Adopting drought-tolerant (DT) cultivars is an effective strategy to sustain maize (Zea mays L.) production under water shortage. Optimizing plant density is an important management practice for improving maize yield. In a two-year field trial, the response of yield, actual evapotranspiration (ET c act), and water productivity (WP) to plant density (6, 7.5, 9 plants m−2) was assessed under irrigated and rainfed conditions using a DT (ZD958) and a drought-susceptible (DS, ZY309) maize cultivar, and additionally, the comparison of soil water depletion will be conducted among soils growing different DT maize varieties. Under rainfed, average yield, ET c act , and WP were 24.7%, 8.6% and 14.8% greater in ZD958 than ZY309, respectively. When density increased from 6 to 9 plants m−2, for ZD958 and ZY309 ET c act remained relatively constant, whereas their yield and WP first increased and then decreased and ultimately reached their maximum at 7.5 plants m−2. Under irrigation, increasing density (6–9 plants m−2) significantly increased yield and WP for ZD958, but for ZY309, yield and WP were not significantly impacted. Yield across seasons did not differ between cultivars at 6 and 7.5 plants m−2, and ZD958 had a 10.2% yield advantage over ZY309 at 9 plants m−2. The findings imply that DT cultivar showed greater high density tolerance than DS cultivar and thus higher optimal density under irrigation. Under rainfed, both cultivars had similar density tolerance and optimum density, whereas DT cultivar had stronger drought tolerance than DS cultivar, which could explain DT cultivar's greater yield and WP. This study indicate that DT cultivar showed higher and more stable yields than DS cultivar across rainfed and irrigated conditions when grown at optimal densities. Thus, sustainable maize production could be achieved by adopting DT cultivars and optimizing density for different conditions in the study region. • Drought-tolerant cultivar had greater crowding tolerance than drought-susceptible cultivar under irrigation. • Crowding tolerance did not differ between drought-tolerant and drought- susceptible cultivars under rainfed. • Higher tolerance of drought-tolerant cultivar accounts for its higher yield and water productivity under rainfed. • Higher optimum density found in drought-tolerant vs. susceptible cultivar under irrigation but not under rainfed. • Drought-tolerant cultivar extracted more soil water than drought-susceptible cultivar under rainfed. [ABSTRACT FROM AUTHOR]

The supersonic separation is a novel technology in the natural gas dehydration for its compact design and fewer emissions. The other fascinating advantage is that the diffuser can convert kinetic energy into pressure energy to improve the energy efficiency. The mechanism of the pressure recovery is not well understood for the various flow conditions in supersonic velocities. The maximum pressure recovery coefficient (PRC) was estimated in theory and a theoretical equation was obtained with the ideal gas assumption. The theoretical results indicated that the PRC depended on the gas adiabatic exponent and Mach number in the upstream of the shock wave. A computational fluid dynamics model was developed to evaluate the gas dynamic parameters with various Mach numbers and their effects on the PRC. We found that a higher adiabatic exponent induced a larger PRC when the gas Mach number is more than 1.3. The PRC declined with the increase of the Mach number in the upstream of the shock wave both in the theoretical and numerical predictions. The numerical results are smaller than the ideal data with the maximum error of about 8.69% in the whole computed gas Mach number from 1.15 to 1.87. These results have suggested that the derived theoretical equation can be employed to estimate the PRC in the supersonic separation process to improve the design efficiency. [ABSTRACT FROM AUTHOR]

Herein, we demonstrated that a novel derivative of zeolitic imidazolate framework (ZIF) obtained by direct fluorination (ZIF-67) is an efficient electrocatalyst for Oxygen Evolution Reaction (OER). The obtained catalyst showed the main phase of tetragonal CoF 2 from the metal center and the nitrogen-doped carbon from the ligands of ZIF-67. The polyhedral morphology was well kept but with a more rough surface consisting of assembled nanoparticles. Due to the good conductivity and high polarity in the system, this electrocatalyst showed an overpotential of 294 mV required to yield 10 mA cm−2 with good stability. [Display omitted] • ZIF-67 derived cobalt fluoride is active for oxygen evolution reaction. • The structure of N-doped carbon can increase the conductivity of the catalyst. • The obtained CoF 2 from the metal center has high polarity. • Extending the application of the novel derivative by direct fluorination of MOF-based materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe and Ni sites were selectively separated by melamine-assisted MOF pyrolysis. • The fluorination process selectively forms FeF 2 rather than NiF 2. • Theoretical and spectral techniques confirmed FeF 2 transformation to active FeOOH. • Enhanced electronic interactions and adsorption energy underscore the impact of fluorination. • Regulation of Fe sites and their synergistic effect with Ni improved catalytic performance. Given its initially low activity and difficulty in active phase formation, Fe site regulation is rarely touched in FeNi-based oxygen evolution reaction (OER) catalysts. Herein, the Fe sites regulation and activity deciphering are demonstrated by selective phase transformation taking nitrogen-doped carbon confined FeNi nanoparticles derived from Fe 2 Ni-MIL-MOF pyrolysis as an example; driven by the reduction atmosphere and Kirkendall effect assisted by melamine pyrolysis, some Fe and Ni sites were separated to form metallic Fe and FeNi alloy and the subsequent fluorination process induced the ionic compound FeF 2 formation rather than NiF 2 , offering a good platform to evaluate the influence of active Fe phase for OER catalysis. Theoretical calculations combined with ex-situ and in-situ spectral characterization techniques proved the complete convention of FeF 2 into a high-valent and reactive intermediate state of FeOOH. Considering the stable metallic state of Ni, the largely improved catalytic performance could be attributed to the Fe site regulation and the subsequent synergistic catalysis effect. Compared to the traditional iron-based catalyst, theoretically, the electronic structure of FeF 2 was more conducive to the active FeOOH phase formation and significantly lowered the reaction energy barrier for OER. By addressing the aforementioned problems, low overpotential and good stability for OER catalysts were realized. The current work showed valid proof of the FeNi-based catalysts regulation via Fe sites for energy-relevant catalysis reactions. [ABSTRACT FROM AUTHOR]

• A holistic water quality assessment was conducted in the Erdao Songhua River Basin. • The IWPI showed "Good" water quality with spatiotemporal variations in studied basin. • PI, DO, COD cr , and BOD 5 are the most important parameters in this basin. • The potential risks of point source and non-point source pollution in middle-downstream should be of concern. The Erdao Songhua River provides drinking water for 16.82 million people; therefore, ensuring that the water quality adequate is of particular concern. In this study, an improved water pollution index (IWPI) and multiple statistical methods were employed to assess the overall water pollution situation and investigate spatiotemporal variations of seven physicochemical parameters such as the permanganate index (PI), dissolved oxygen (DO), chemical oxygen demand (COD cr), five-day biochemical oxygen demand (BOD 5), total nitrogen (TN), total phosphorus (TP) and ammonia nitrogen (NH 3 -N), which were collected monthly at 20 sites within the mainstream and major tributaries of the Erdao Songhua River Basin (ESRB) from 2015 to 2020. Stepwise regression analysis was conducted to build a minimum improved water pollution index (IWPImin) model consisted of four key elements (PI, DO, COD cr , and BOD 5) proposed from seven parameters. The results demonstrated water quality within the ESRB was considered to be "Good" with the mean IWPI values <40. However, the water quality deteriorated from the upstream to the downstream within the basin, manifested as the mean value of IWPI of the downstream is 1.7 times of upstream. Seasonally, an improving trend of water quality was observed during the monitoring period and the mean IWPI value decreased by 23%. Furthermore, Seasonal variation in the IWPI value was evident, and the best water quality was found in winter (lowest IWPI value of 14.1) and the worst in summer (highest IWPI value of 21.7). The proposed IWPImin model uses the selected four crucial parameters and the weights of those parameters has exhibited excellent performance in the water quality assessment, with the highest coefficient of determination (R2) and lowest Root Mean Square Error (RMSE) values of 0.996 and 0.51, respectively, which can be used to optimize water quality assessment strategies at a lower cost. For future management, the water quality of middle and downstream should be carefully inspected, and strictly control the effects of point source and non-point source pollution in the ESRB. [ABSTRACT FROM AUTHOR]

Support engineering modulated Pt by hierarchical MoSe 2 @mesoporous hollow carbon support well addressed the challenges in low intrinsic activity and easy poisoning problems during methanol electrolysis. [Display omitted] • Electrochemical energy conversion from methanol to hydrogen via methanol electrolysis. • Support engineering modulated Pt by hierarchical MoSe 2 @mesoporous hollow carbon support. • Strong interaction and coupling ability between Pt and MoSe 2 regulated the active centers. • Weakened binding strength of CO ad and H ad intermediates during catalysis. • High electrochemical properties due to enhanced oxophilicity and poisoning tolerance ability. Hydrogen generation from methanol via methanol-assisted water splitting is a promising electrochemical energy conversion technology but still meets challenges in addressing the low intrinsic activity and easy poisoning problems of the conventional Pt catalysts. Herein, the support engineering modulated Pt by hierarchical MoSe 2 @mesoporous hollow carbon support was proposed to integrate some structural and catalytic advantages for hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR). Supporting engineering by layered MoSe 2 nanosheets confined in mesoporous hollow carbon spheres (MHCSs) is adopted to uniformly anchor Pt nanoparticles (Pt/MoSe 2 @MHCS), which effectively enhances the conductivity and prevents the layer-by-layer stacking of MoSe 2 ; Strong interaction and coupling ability between Pt and MoSe 2 and the resultant electronic structure regulation of the active centers could weaken the binding strength of CO* and H* intermediates during catalysis and strengthen the oxophilicity leading to improved MOR and HER kinetics. Specifically, Pt/MoSe 2 @MHCS shows a significantly improved MOR current density of 81.1 mA cm−2, about 3.0 times that of the benchmark Pt/C catalyst. Meanwhile, it also exhibits the HER performance of 28 mV to achieve a kinetic current density of 10 mA cm−2 in methanol-contained electrolytes. When employed for overall methanol electrolysis, a lowered input voltage of 1.11 V can be obtained to drive the current density (10 mA cm−2) compared to that for water electrolysis (0.62 V vs. 1.73 V). The electrochemical properties of high activity, rapid catalytic kinetics, and good stability were also demonstrated due to the enhanced oxophilicity and high poisoning tolerance ability resulting from the MoSe 2 /carbon substrate-induced electron redistribution of Pt sites. This work reports a novel platform to address the catalysis challenges in hydrogen production via the methanol electrolysis technique. [ABSTRACT FROM AUTHOR]

Long chain fatty acids are converted to acyl-CoAs by acyl-CoA synthetase (fatty acid CoA ligase: AMP forming, E.C. 6.2.1.3; ACS). Escherichia coli has a single ACS, FadD, that is essential for growth when fatty acids are the sole carbon and energy source. Rodents have five ACS isoforms that differ in substrate specificity, tissue expression, and subcellular localization and are believed to channel fatty acids toward distinct metabolic pathways. We expressed rat ACS isoforms 1-5 in an E. coli strain that lacked FadD. All rat ACS isoforms were expressed in E. coli fadD or fadD-fadR and had ACS specific activities that were 1.6-20-fold higher than the wild type control strain expressing FadD. In the fadD background, the rat ACS isoforms 1, 2, 3, 4 and 5 oxidized [14C]oleate at 5 to 25% of the wild type levels, but only ACS5 restored growth on oleate as the sole carbon source. To ensure that enzymes of β-oxidation were not limiting, assays of ACS activity, β-oxidation, fatty acid transport, and phospholipid synthesis were also examined in a fadD fadR strain, thereby eliminating FadR repression of the transporter FadL and the enzymes of β-oxidation. In this strain, fatty acid transport levels were low but detectable for ACS1, 2, 3, and 4 and were nearly 50% of wild type levels for ACS5. Despite increases in β-oxidation, only ACS5 transformants were able to grow on oleate. These studies show that although ACS isoforms 1-4 variably supported moderate transport activity, β-oxidation, and phospholipid synthesis and although their in vitro specific activities were greater than that of chromosomally encoded FadD, they were unable to substitute functionally for FadD regarding growth. Thus, membrane composition and protein-protein interactions may be critical in reconstituting bacterial ACS function. [ABSTRACT FROM AUTHOR]

• Feedstock particle size and pyrolysis temperature both impact biochar properties. • Finer feedstock pyrolyzed at 300 °C decreased soil N 2 O and CO 2 emission rates. • Finer feedstock pyrolyzed at 300 °C increased net nitrification rates. • Particle size effect on N 2 O and CO 2 emission lessened with pyrolysis temperature. Atmospheric greenhouse gas (GHG) concentration increases are a serious problem impacting global climate. Mitigation of agricultural GHG production is crucial as fertilized soils contribute substantially to changes in GHG atmospheric composition. Biochar derived from agricultural or forestry biowaste has been widely used in agriculture and may help mitigate GHG emissions. While different kinds of biochar and their effects on GHG emissions have been studied, feedstock particle size may interact with pyrolysis temperature to impact biochar effects on GHG emissions, but this has not been investigated. Here, feedstock particle size effects on biochar characteristics and soil nitrous oxide (N 2 O) and carbon dioxide (CO 2) emissions were studied using Camellia oleifera fruit shell feedstock with three particle size fractions (0.5–2, 2–5, and 5–10 mm) each pyrolyzed at 300, 450, and 600 °C. Results showed that dissolved organic carbon in biochar increased with particle size when pyrolyzed at 300 °C, but decreased with pyrolysis temperature. The 0.5–2 mm shell-derived biochar was associated with the lowest N 2 O and CO 2 emission rates but the highest net nitrogen mineralization rates compared to 2–5 mm and 5–10 mm shell-derived biochar when pyrolyzed at 300 °C. Overall, shell particle size was more important for soil processes at lower pyrolysis temperatures with less variation among particle sizes at higher pyrolysis temperatures. The results indicated that feedstock particle size may interact with pyrolysis temperature and impact mitigation of soil N 2 O and CO 2 emissions. [ABSTRACT FROM AUTHOR]

• Provides a protocol for transferring hydrological knowledge between basins. • Proposes a TL-Transformer model for flood simulation and forecasting in data-sparse basins. • Explores the impact of data quality on transfer learning effectiveness. • Explains the manifestation of hydrological similarity in transfer learning through topographic index. • Compares the performance of models including physical and neural network models. There exists a substantial disparity in the distribution of streamflow gauge and basin characteristic information, with a majority of flood observations being recorded from a limited number of well-monitored locations. Transferring hydrological knowledge from data-rich to data-sparse basins has been a persistent issue. While artificial intelligence methods, such as Long-Short-Term Memory Neural Networks (LSTMs) have been attempted for simulating across different basins, the problem of gradient vanishing still inevitably lead to difficulties in responding to new basin datasets. A novel solution is presented in the form of the Transfer Learning Framework based on Transformer (TL-Transformer), which can accurately predict flooding in data-sparse basins (targets) by using models from data-rich basins (sources) without requiring extensive basin attributes at the target location. The framework was demonstrated in the middle reaches of the Yellow River, and performance was evaluated using the Nash Sutcliffe efficiency coefficient, root mean square error, and bias. The results show that TL-Transformer outperforms other models, including TOPMODEL, MLP, TL-MLP, LSTM, TL-LSTM and Transformer in all target basin stations. Compared with those models that without transfer learning, TL-Transformer showed significantly improved performance, where NSE increased by 0.2 and reached above 0.75, RMSE and bias were also controlled within 60 and 20, respectively. Furthermore, pre-training on basins with hydrological similarities increases the benefits of Transfer Learning, and we explained this response phenomenon through the topographic index. These results suggest that deep learning can tap into the commonalities in hydrological data across basins to improve the accuracy of flood forecast applications in areas with limited observations. [ABSTRACT FROM AUTHOR]

Atomic layer deposition (ALD) plays a pivotal role in raising the long-term stability of perovskite quantum dot (PQD). The deposition temperature of excellent alumina film prepared by ALD is generally higher than 200 °C. In such a temperature environment, the lattice morphology of PQD is seriously damaged. In this work, to effectively protect PQD, the optimum temperature for depositing alumina on the surface of CsPbBr 3 PQD is investigated. The CsPbBr 3 PQD is deposited on a transparent glass substrate. Subsequently, an alumina layer is deposited on the surface of PQD via ALD at a deposition temperature of 40–120 °C. In our experiment, the significant degradation of PQD is observed when the deposition temperature of ALD is set to 80 °C and above. Lowering the deposition temperature can effectively improve the optical performance of PQD. The samples with alumina deposited at 75 °C show excellent stability after undergoing aging tests, and therefore 75 °C is considered the best ALD temperature. Besides, white light-emitting diode (W-LED) is produced by a method that a stack structure consisting of CsPbBr 3 coated via ALD at 75 °C and CdSe QD is excited using blue Micro-LED, and the color gamut of W-LED accounts for the wide area of 94.00% NTSC (1953) and 86.20% Rec.2020 displayed wide color gamut features. The experiment provides practical guidance for selecting the optimal deposition temperature for ALD-packaged PQD-based devices. • An optimum temperature for depositing alumina on CsPbBr 3 via ALD is investigated. • Low temperature ALD technology can effectively passivate the surface defects of CsPbBr 3. • Samples have preferable environmental stability after coating with Al 2 O 3. [ABSTRACT FROM AUTHOR]

Abstract Shortening the bainite transformation time is one crucial issue on the application of high carbon nano-bainite steel. In this paper, an accurate black-box model that could predict the plate thickness of bainitic ferrite was constructed based on gradient boosting decision tree model, and a polynomial model was constructed to make predicting process easier. According to the constructed model, a two-steps process was proposed, which shortened the transformation time from over 60 h to nearly 25 h. After the new process treatment, the size distribution of bainitic ferrite in microstructure became more uniform, and the strength and toughness of steel were also improved simultaneously. [ABSTRACT FROM AUTHOR]

Shape memory materials with controllable property for harsh condition like high temperature are strongly required. Here, three novel shape memory polyimides (SMPIs) have been realized by bearing various side-chain groups (-H, –CH 3 or –OCH 3) to study their relationship between structures and shape memory performances. These PIs possess excellent shape memory behaviors in both fixity ratio (R f > 99.1%) and recovery ratio (R r > 86.8%). The rheological information revealed different creep and stress relaxation accompanied with the different SMPIs. Meanwhile, fractional free volume (FFV) and simulating of geometry optimized molecule chain via Materials Studio were referred to reveal the inner relationship between shape memory performance and polymer structure. This work provides a design metric to guiding significance to the structure design of shape memory polyimides. • Three shape memory polyimides with various chain side groups are manufactured. • The SMPIs possess excellent shape memory behaviors. • Rheological properties and molecular simulation are discussed. [ABSTRACT FROM AUTHOR]

The removal of Ni (II), Cu (II), Zn (II), and Co (II) ions from simulated aqueous solutions using calcium silicate powder (CSP), a new by-product derived from the production of alumina from coal ash, has been studied. CSP showed high efficiency for the removal of these metal ions. The maximum adsorptions were 420.17, 680.93, 251.89, and 235.29 mg/g for Ni (II), Cu (II), Zn (II), and Co (II), respectively. Total (100%) removal of Ni (II) was obtained when the initial concentration was 100 mg/L, indicating that CSP was highly effective even at an extremely low concentration. Adsorption isotherms and kinetics have been studied using different models. It has been found that the adsorption isotherms can best be described on the basis of the Langmuir model, with the kinetics of adsorption following a pseudo-second-order reaction process. The calcium ion concentration was examined before and after adsorption to investigate the mechanism of removal of the heavy metal ions. It was found that the removal of heavy metal ions is mainly achieved through ion-exchange, combined with some adsorption. [ABSTRACT FROM AUTHOR]

• Urea oxidation catalyzed by NiSe 2 largely improved by a facile Fe doping strategy. • Doping amount of Fe would greatly impact the catalytic ability. • NiSe 2 with 1.68 at.% Fe-doping exhibited the best catalytic performance. • Current density at 1.54 V was 4.4 times higher than that of pristine NiSe 2 electrode. • The cell voltage of 1.45 V to reach 10 mA cm−2 was 170 mV lower than water electrolysis. The non-precious Ni-based catalysts are promising in the electrooxidation of urea while the low intrinsic activity still needs to be increased for practical application. Herein, we demonstrated the urea oxidation catalyzed by NiSe 2 nanorod could be greatly improved by Fe doping strategy. The Fe-doping effect was probed by density functional theory which revealed that doping could enhance the interface electric field inducing the charge redistribution near the Ni atom, and enhancing the adsorption capacity of Ni to urea molecules. As a result, the balanced interaction of Fe/Ni synergism and the Ni active site exposure can be realized by tuning the Fe doped amount in the system, which would greatly impact the catalytic ability and intrinsic performance. The NiSe 2 with 1.68 at.% iron doping demonstrated the highest catalytic performance for urea oxidation, displaying the largest surface-active area, highly efficient kinetics, fast charge transfer rate, and outstanding stability. The current density of 125.8 mA cm−2 for urea oxidation catalyzed by Fe doped NiSe 2 electrode was obtained at 1.54 V vs. RHE when supported on the glassy carbon electrode, almost 4.4 times that of the pristine NiSe 2 electrode. When constructed in the two-electrode system combined with the commercial Pt/C cathode, the cell voltage used for urea electrolysis was 1.45 V to provide the specific current density of 10 mA cm−2, approximately 170 mV lower than that of pure water electrolysis, indicating the potential application of hydrogen generation for urea-assisted water splitting. The urea oxidation catalyzed by NiSe 2 nanorod can be largely improved by a facile Fe doping strategy, and the doping amount of Fe would greatly impact the catalytic ability and intrinsic performance. [Display omitted] [ABSTRACT FROM AUTHOR]

Two kinds of new electroactive polyamides were synthesized from a novel diphenylamine-fluorene skeleton bis(ether amine) monomer “ N,N -bis((4-aminophenoxy)phenyl)-2-amino-9,9-dimethylfluorene” with cycloaliphatic and aromatic dicarboxylic acids, respectively. These polyamides were highly soluble in many organic solvents and could be solution-cast into transparent and flexible films. These films were nearly colorless with the optical transmittance over 90% at 450 nm and the cut-off wavelengths in the range of 385–390 nm. These polyamides revealed reversible redox with a strong color changing from colorless (neutral state) to green (oxidation state), and the electrochromic contrast of transmittance was up to 86% at 410 nm. Especially, the polyamide derived from cycloaliphatic acid exhibited strong blue fluorescence emission with the quantum yield up to 14.5% and 58.9% in solid state and solution state, respectively. Furthermore, the fluorescence of the polyamide film could be reversibly and readily modulated by electrochemical redox exhibiting a high contrast of 83. [ABSTRACT FROM AUTHOR]

• Provides a protocol to optimize hyperparameters of LSTM. • Proposes a PSO-LSTM model for flood simulation and forecast. • Study the effect of hyperparameter changes on LSTM results. • Explores the optimal hyperparameter combination of LSTM at different lead times in flood forecast, and achieve the best simulation results by optimizing model hyperparameters. • Compares the performance of the models including physical and neural network models. Flood forecasting is an essential non-engineering measure for flood prevention and disaster reduction. Many models have been developed to study the complex and highly random rainfall-runoff process. In recent years, artificial intelligence methods, such as the artificial neural network (ANN), have attempted to construct rainfall-runoff models. The more advanced deep learning methods of long short-term memory (LSTM) network have been proved to better predict hydrological time series. However, the selection of LSTM hyperparameters in the past mostly relied on the experience of the staff, which often led to failure to achieve the best performance. The aim of this study is to develop a method to improve flood forecast accuracy and lead time. A deep learning neural network model based on LSTM networks and particle swarm optimization (PSO) is proposed in this paper. The PSO algorithm was used to optimize the LSTM hyperparameter to improve the ability to learn data sequence features. The model focuses on the Jingle Watershed in the Fenhe River and the Lushi Watershed in the Luohe River and was used to predict flood processes using rainfall and runoff observation data from stations in the watersheds. We evaluated the performance of the model with the Nash Sutcliffe efficiency coefficient, root mean square error, and bias. The results show that the PSO-LSTM model outperforms the M-EIES, ANN, PSO-ANN, and LSTM at all stations in the watersheds. The PSO-LSTM model improves the flood forecasting accuracy at different lead times, especially for those exceeding 6 h, and has higher prediction accuracy and stability. The PSO-LSTM model could be used to improve accuracy in short-term flood forecast applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] The more the porosity, the lower the pressure inside FADS. [•] The higher the porosity, the poorer the uniformity of air velocity distribution. [•] The effect of fiber diameter is similar with the effect of porosity. [•] Increasing air flow rate aggravates the nonuniformity of air velocity distribution. [•] Results would help guide the optimum design of FADS in penetration mode. [ABSTRACT FROM AUTHOR]

Abstract: There is a rapidly increasing demand for hydropower in China. However, little research has been conducted to systematically investigate the overall aspects of hydropower development risks. With support of the data collected from a fieldwork survey, this study reports the multiple facets of hydropower development risks in China as perceived by main project participants. All groups have a common view on the criticality of safety, and the groups also have their own priorities, i.e., resettlement of migrants, incompetence of subcontractors, project delay, inadequate or incorrect design, premature failure of facilities and ecological and environmental impacts are the key risks to clients, whereas quality of work, financial related risks, reputation, and claims and disputes are the main concerns to contractors. A case study of Three Gorges Project further demonstrates that, hydropower development risks can be effectively managed by encouraging joint efforts of all participants to achieve the goals on producing renewable energy, reducing emissions of CO2, and providing important social/economical benefits. Future hydropower development should emphasize the interactions between project delivery, environmental, and economical processes to reach appropriate trade-offs among involving stakeholders, by adequately considering the inter-relations between project participants' risks as well as hydropower project's externalities on a broad view. [Copyright &y& Elsevier]