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To produce high performance low carbon MgO–C refractories, the combustion synthesized MgO nanofibers containing C/MgO composite powders (SCM) were introduced. The effect of SCM on the mechanical properties, thermal shock resistance, oxidation resistance and slag resistance of MgO–C refractories has been studied, along with exploring the toughening mechanism on thermal shock resistance. The results showed that the refractories containing 6 wt% SCM (M6) exhibited the most favorable comprehensive properties. Compared to reference sample M0, M6 showed significant enhancements in thermal shock resistance, oxidation resistance, and slag resistance by 38.6%, 29.8%, and 23.9%, respectively. Notably, the unique microstructure of MgO nanofibers and carbon encapsulated MgO played a crucial role in facilitating crack deflection and branching, which promote the generation of microcracks and the consumption of strain energy. These mechanisms contributed to the improvement in thermal shock resistance of refractories. [ABSTRACT FROM AUTHOR]

The hydrogen diffusion and damage characteristics within the microstructure at the crack tip are direct factors determining hydrogen embrittlement (HE) phenomena, yet research in this area from a mesoscale perspective is still insufficient. This study employs a non-local crystal plasticity constitutive model coupled with a hydrogen diffusion model that considers grain boundary (GB) characteristics and incorporates fracture initiation parameter accounting for the HELP + HEDE mechanisms. The research investigates hydrogen diffusion behavior at the crack tip in pure nickel and provide a detailed exploration of the mechanism underlying hydrogen-assisted crack propagation. The results indicate that the non-local model exhibits advantages in simulating the hydrogen diffusion process. Hydrogen induces intragranular cracks to propagate along slip planes with a high dislocation density. High-energy GBs and triple junctions are more susceptible to hydrogen accumulation, and under the influence of the HEDE mechanisms, they represent the primary sites for crack initiation. The entire fracture process involves the continuous coalescence of primary cracks with secondary cracks. Moreover, the HE resistance is better in equiaxed microstructures compared to rolled microstructures, particularly when the crack plane is parallel to the TD direction. • The hydrogen diffusion behavior in the microstructure at the crack tip was studied. • The interaction between hydrostatic stress and strain induces hydrogen-assisted cracking. • High-energy GBs serve as the primary enrichment sites for hydrogen atoms. • The HE resistance of the rolled microstructures is inferior to the equiaxed ones. [ABSTRACT FROM AUTHOR]

C/MgO composite powders were prepared by combustion synthesis using magnesium oxalate and magnesium powders as raw materials. The phase composition and microstructure of the composite powders were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy/energy dispersive spectroscopy (FESEM/EDS), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The synthetic mechanism was explored through TG-FTIR and combustion front quenching techniques. It was found that the C/MgO composite powders contained a large quantity of MgO nanofibers. When the molar ratio of magnesium oxalate and magnesium was 1:4, the carbon content of the product reached a maximum of 9.45 wt %. In the composite powders, cubic MgO particles were encapsulated by a thin carbon layer, and there was a tiny gap between MgO and the carbon layer; a large number of MgO nanofibers with aspect ratios of 80–100 were found. The cubic MgO particles of the products are the direct decomposition of MgC 2 O 4 , and the MgO nanofibers are the reaction product of gaseous Mg and CO 2 /CO at high temperature. Meanwhile, the carbon deposited on the MgO particles can inhibit the grain growth of MgO particles and result in the refinement of MgO particles. The uniform dispersion of carbon and the weak C/MgO interface combine, making the composite powders a potential additive for low-carbon MgO–C refractories with excellent thermal shock resistance. [ABSTRACT FROM AUTHOR]

• A novel hydrogen diffusion model coupled with CPFE framework was proposed. • The GB energy and HS jointly determine the distribution of hydrogen. • Hydrogen diffusion along GB is affected by the concentration within the grains. • Alloys with medium-sized grain microstructures exhibit good hydrogen tolerance. The influence of grain boundaries (GBs) on hydrogen transportation is a crucial factor in understanding the mechanisms of hydrogen embrittlement (HE) in polycrystalline alloys. Crystal plasticity models have the advantages in simulating the effect of grain microstructure on hydrogen diffusion in polycrystals, but they have not yet been coupled with hydrogen diffusion models that can take into account GB characters. In this study, a hydrogen diffusion model that considers the effect of GBs on the transportation of hydrogen was developed to study the local hydrogen diffusion behavior in bi-crystalline and polycrystalline alloys. The simulation results showed the capability of the model in describing the influence of hydrogen on the material deformation. In addition, this study found that the hydrostatic stress determined the hydrogen concentration in the far-GB region, whereas the GB energy played a control role in and near the GB regions. Notably, hydrogen exhibits a preference for localization near high-angle grain boundaries (HAGBs) and triple junctions. In alloys with medium grain size, hydrogen typically had low average concentration with a more uniform distribution. Furthermore, the hydrogen-assisted crack growth mechanism was analyzed as the continuous coalescence of primary and secondary cracks along GBs. This work presents a hydrogen diffusion model that considers GB effects, and the proposed model has advantages in predicting the deformation and fracture of polycrystalline alloys in hydrogen environments. [ABSTRACT FROM AUTHOR]

Abstract In this work, nanosheet-shaped CuS (NS CuS) is successfully grown on carbon cloth (CC) by a two-step route in combination with electrodeposition and hydrothermal treatment via in situ sulfidations of Cu 2 O and Cu with exposure to thiourea at 120 °C or 24 h. Transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffractometry are performed to characterize the microstructure, morphology, composition, and crystal structure of the NS CuS CC samples. The electrochemical measurements demonstrate that the synthesized NS CuS CC electrocatalysts possess outstanding oxygen evolution reaction (OER) performance and superior long-term durability in 1 M KOH electrolyte. In particular, the NS CuS CC synthesized via the electrodeposition process at an applied current of 1.5 mA shows a low overpotential for the OER (358 mV at 10 mA/cm2), which is close to that of commercial IrO 2 (346 mV at 10 mA/cm2). The exceptional OER property is ascribed to the NS CuS having a large surface area to offer abundant reaction active sites and to the CC network structures supplying more ions and charge transfer channels during the electrocatalytic process. [ABSTRACT FROM AUTHOR]

Many fish swim using various kinematic patterns of head and tail combinations to change their body posture, which reduces drag while swimming. This study proposes a new method to improve the energy-harvesting performance of a flapping foil by actively controlling the combined movements of the leading- and trailing-edge flaps. These movements allow the foil to deform to a shape with preferable hydrodynamic performance during the flapping motion inspired by fish swimming modes. The study employs two-dimensional (2D) computational fluid dynamics (CFD) simulations to investigate the effect of the forced oscillation of a leading-edge flap on the energy-harvesting performance of a flapping foil. Consequently, the optimal combination of operating parameters of the leading-edge flap leading to greater efficiency and an apparent increase in power production from the flapping foil can be determined. Therefore, the energy-harvesting performance of a flapping foil with dynamic leading- and trailing-edge flaps was investigated numerically. The results suggest that synchronized movement between the leading- and trailing-edge flaps, which mimic the movement of live fish, can increase the camber of the foil and effectively manage the boundary layer by adjusting the frequency and amplitude of the oscillations, thereby generating elevated hydrodynamic forces acting on the foil. Therefore, the proposed flapping foil with swinging leading- and trailing-edge flaps can exhibit superior energy-harvesting performance than its conventional alternative across the full spectrum of operations. • A novel concept of a flapping foil flow energy harvester is proposed in this work. • Actively controlled leading- and trailing-edge flaps were adopted to mimic the head and tail oscillations of a fish. • CFD analysis were performed to investigate the performance of the proposed flapping foil configuration. • The proposed flapping foil energy harvester has better energy harvesting performance than its conventional counterpart. [ABSTRACT FROM AUTHOR]

Exposure to pesticides has been proposed to be a positive association in suicide and suicidality. Many studies have explored this topic, but have reported inconsistent findings. We carried out a systematic review and meta-analysis of the now existing evidence on the association between pesticide exposure and the risk of suicide and suicidality. We searched PubMed, EMBASE and Web of Science databases for studies published up to February 1, 2023. For studies that provided detailed data, we applied quantitative meta-analysis to calculate Odds ratio (OR) with 95% Confidence Intervals (CIs) to evaluate the results. Heterogeneity among the included studies was assessed using Cochran's Q test, I 2 statistic and tau-squared (τ2). Publication bias was evaluated by funnel plots, Egger's test, and Begg's test. In addition, subgroup analyses according to pesticides category and geographical area were performed. 2906 studies were initially identified, and 20 studies were eventually included. Fifteen of the studies were on suicide deaths and suicide attempts, and five were on suicidal ideation. Pesticide exposure was positively related to suicide deaths and suicide attempts (pooled OR = 1.31; 95%CI: 1.04–1.64, p < 0.001) and suicidal ideation (pooled OR = 2.43; 95%CI: 1.51–3.91, p = 0.015). In the subgroup analysis, mixed pesticide type (pooled OR = 1.55; 95%CI: 1.39–1.74) increased the risk of suicide deaths and suicide attempts. The results of the analysis by geographic area showed that the risk of suicide deaths and suicide attempts with pesticide exposure was 2.27 (95%CI = 1.36–3.78), and 1.33 (95%CI = 1.14–1.56) in Asia and Europe, respectively. The risk of suicidal ideation caused by pesticide exposure in Asia and America were 2.19 (95%CI = 1.08–4.42) and 2.99 (95%CI = 1.76–5.06). In conclusion, pesticide exposure may increase the risk of suicide and suicidality based on the current evidence. • Evidence on pesticide exposures and suicidality risk remains inconsistent. • The review identified 20 studies including nearly 20 million persons. • We included three dimensions of suicide (death, attempt, ideation). • Exposure to pesticides is associated with higher risk of suicide and suicidality. [ABSTRACT FROM AUTHOR]

Cooling char, which is prepared in an inert atmosphere and then reacted with oxygen after cooling, has been widely used in the kinetic study of char combustion. However, there is no cooling process in commercial combustion systems and thus the impacts of the cooling process on char reactivity remain unclear. To illustrate this question, a two-step reaction analyzer was developed to study the combustion kinetics of in-situ char, which was produced at a constant high temperature in an inert atmosphere and then directly reacted with oxygen at different temperatures. Two types of Chinese coal, Shenhua sub-bituminous coal and Yangquan anthracite, were selected as samples. The results showed that the reaction rate of in-situ char was about 1.1–1.25 times of that of rapid cooling char, suggesting that the cooling process has a significant effect on char reactivity. Then the combustion rate and structure of chars cooled at different cooling rates were investigated to determine the reason for char deactivation during the cooling process. The cooling char reactivity decreased with the decreasing cooling rate, but the specific surface area did not decreased considerably. This result revealed that char deactivation during the cooling process was independent of specific surface area. As the cooling rate decreased, the oxygen chemisorption capacity (active surface area) of cooling char decreased for Shenhua coal, indicating that the observed char deactivation during the cooling process might be caused by the decrease of active surface area. In addition, Yangquan anthracite, as a high rank coal, was less sensitive to the cooling process due to its higher carbon crystallites and provision of fewer active sites for oxidation. [ABSTRACT FROM AUTHOR]

Abstract To assess the seasonal and spatial variations and long-term trends in water optical properties in Lake Fuxian, investigations based on field work in four seasons and a long-term analysis of data from 1980 to 2014 were conducted. The results show that there was no significant variation in the euphotic depth (Z eu) across the four seasons, and no significant correlations between Z eu and potential influencing factors in seasons other than summer, suggesting that the water itself may be a major factor regulating the Z eu in general. Nevertheless, significant differences in Z eu between the north region (NR) and the south region (SR) were observed in all seasonal tests except spring. This finding relates to a higher abundance of chromophoric dissolved organic matter (CDOM) in the NR due to runoff, especially in the rainy seasons (summer and autumn). CDOM and its terrigenous component had an important impact on Z eu in summer, with the highest precipitation, and impacts from suspended solids and non-algal particles were also found in the NR in summer. The Secchi disk depth in the lake decreased clearly over the years, with significantly negative correlations with the increasing permanganate index and air temperature, implying that organic contaminants (CDOM and/or phytoplankton) are important regulators of water transparency. We estimate that the combined effects of climate warming and changes in land use and land cover are also indirect regulating factors. These findings should be considered in the protection of Lake Fuxian, owing to the importance of light penetration in aquatic ecosystems. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

We report herein a one-pot synthesis of unsymmetrical disulfides with trichloroisocyanuric acid (TCCA) as an oxidant. Under facile conditions, aromatic-aromatic disulfides and aromatic-aliphatic disulfides were synthesized in good to excellent yields even without base. For the construction of the challenging aliphatic-aliphatic disulfides, good yields of the desired products were also obtained with slightly modified conditions. Additionally, the reactions demonstrated a wide range of substrate scope, very short reaction time (<5 min), and convenient procedures. [ABSTRACT FROM AUTHOR]

• Serrated flow mechanisms during plane-strain compression were revealed. • Dynamic recrystallization was accelerated at high strain rate. • <001>were preferred crystallographic orientations to recrystallization nucleation. • Improving volume fraction of DRX grains can weaken texture intensity. [Display omitted] Strain rate played an important role in the forming process of metal and alloy. In the present work, the effect of strain rate on deformation behavior and microstructure evolution of thermal-rolled Inconel 625 superalloy were systematically investigated by plane-strain compression (PSC) test at 1000 °C, and the strain rate range changed from 1 × 10−3 s−1 to 5 s−1. Obvious serrations occurred in strain rate range of 5 s−1 - 0.05 s−1 and transformed from type A to type A+B, and type B with decreasing of strain rate. Microscopic observations from transmission electron microscopy (TEM) indicated that type A and type B serration were related to slip bands nucleation-propagation, and carbon atoms-dislocations interaction, respectively. Electron backscatter diffraction (EBSD) technique and TEM were used to study the dynamic recrystallization (DRX) behavior during PSC. As the strain rates were greater than 5 s−1, DRX process was accelerated because of high deformed stored energy and adiabatic heating. This is undoubtedly a meaningful find to refine grain size and improve thermal processing efficiency. Discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) have been confirmed to occur simultaneously during the deformation process, but CDRX played a minor role in DRX nucleation. Texture evolution characteristics were also related to strain rate. Nearly random texture distribution was obtained as the strain rate above 0.5 s−1. Obvious Cu, E, S and Cube textures appeared in the strain rate range of 0.1 s−1–10−2 s−1. Grain orientations showed random distribution at the strain rate of 10−3 s−1. Moreover,<001> direction should be considered as preferred crystallographic orientations to recrystallization nucleation. [ABSTRACT FROM AUTHOR]

Herein, MoS 2 /CdSe/TiO 2 ternary composites have been successfully synthesized by a simple approach. The SEM and TEM results demonstrate that MoS 2 /CdSe/TiO 2 ternary composites have a porous structure, which can provide more active sites and mass charge transport pathways in a catalytic system. The optical measurement demonstrates that the MoS 2 and CdSe coexisted in the porous TiO 2 structure, which results in a wider visible light absorption than that of pure TiO 2. Most importantly, the photoelectrochemical measurement results demonstrate that such ternary composite catalysts exhibit a higher photocurrent performance than that of a binary composite and pure TiO 2 , owing to the strong synergistic effects among MoS 2 , CdSe, and TiO 2. These superior results show that MoS 2 /CdSe/TiO 2 ternary composites is a promising choice for photoelectrochemical water splitting. Image 1 • Porous MoS 2 /CdSe/TiO 2 photoanodes were prepared by a facile method. • Porous MoS 2 /CdSe/TiO 2 photoanodes can enhance the light absorption and supply more surface reaction active sites. • Porous MoS 2 /CdSe/TiO 2 catalysts can significantly enhance the separate rate of the photogenerated charge carrier. [ABSTRACT FROM AUTHOR]

It is well known that both catalytic efficiency and stability are the two important parameters of photocatalysts for visible-light-driven hydrogen production reactions. However, light-driven hydrogen evolution based applications still suffer from sluggish reaction kinetics due to the lack of high-performance photocatalysts. In this paper, we successfully synthesized a ternary porous CdS/WO 3 /TiO 2 photocatalyst with high efficiency and stability via two-stage approach. The as-prepared samples are characterized by XRD, FESEM, EDS, TEM, XPS, and UV–Vis, respectively, which illustrated that the CdS and WO 3 moieties are in-situ formed inside the porous TiO 2 . Particularly, the photocatalytic hydrogen (H 2 ) evolution rate of such ternary 8% CdS/WO 3 /TiO 2 (molar ration of CdS:WO 3 :TiO 2  = 8:8:100) photocatalyst ranges up to 2106 μmol h −1  g −1 under visible-light irradiation, which is higher than that of pure TiO 2 and other binary (CdS/TiO 2 and WO 3 /TiO 2 ) porous photocatalysts. The superior H 2 evolution efficiency can be attributed to the coexistence of CdS and WO 3 in porous TiO 2 which can promote the interfacial charge transfer and separation as well as extend the light absorption up to the visible range. [ABSTRACT FROM AUTHOR]

Herein, we report a successful synthesis of porous TiO 2 monoliths decorated with unique nanoplate, nanoprism, and nanopyramid-shaped CdSe particles through a mild selenylation of CdO embedded inside porous TiO 2 monoliths via a hydrothermal method in a very controlled manner. Compared with pure TiO 2 , as-synthesized CdSe/TiO 2 photocatalyst not only enhances light absorption but also leads to a highly efficient charge-carrier separation. Particularly, the nanoplate-shaped 7% CdSe/TiO 2 photocatalyst (molar percentages of CdSe to TiO 2 is 7:100) exhibits an exceptional hydrogen evolution rate up to 3650 μmol h −1 g −1 without resorting to any noble-metal co-catalysts under visible-light irradiation owing to synergistic effects envisaged by a rational material design. Our results may provide a useful strategy to develop a highly-efficient visible-light-driven hydrogen production system via water splitting. [ABSTRACT FROM AUTHOR]

Efficient production of hydrogen through visible-light-driven water splitting mechanism using semiconductor-based composites has been identified as a promising strategy for converting light into clean H 2 fuel. However, researchers are facing lots of challenges such as light absorption and electron-hole pair recombination and so on. Here, new sheet-shaped MoS 2 and pyramid-shaped CdS in-situ co-grown on porous TiO 2 photocatalysts (MoS 2 CdS TiO 2 ) are successfully obtained via mild sulfuration of MoO 3 and CdO coexisted inside porous TiO 2 monolith by a hydrothermal route. The scanning electron microscopy and transmission electron microscopy results exhibit that the MoS 2 CdS TiO 2 composites have average pore size about 500 nm. The 3%MoS 2 10%CdS TiO 2 demonstrated excellent photocatalytic activity and high stability for a hydrogen production with a high H 2 -generation rate of 4146 μmol h −1 g −1 under visible light irradiation even without noble-metal co-catalysts. The super photocatalytic performance of the visible-light-driven hydrogen evolution is predominantly attributed to the synergistic effect. The conduction band of MoS 2 facilitates in transporting excited electrons from visible-light on CdS to the porous TiO 2 for catalytic hydrogen production, and holes to MoS 2 for inhibiting the photocorrosion of CdS, respectively, leading to enhancing the efficient separation of electrons and holes. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting using high-performance catalysts shows considerable promise in generating environment-friendly hydrogen energy. Its practical applications, however, suffer from several shortcomings, such as low photocurrent density, large onset-voltage value, and poor durability. In this study, CuS and CdS quantum-dot-cosensitized porous TiO 2 -based PEC catalysts (CuS-CT) have been successfully synthesized via in situ sulfuration of CuO and CdO coexisting inside a porous TiO 2 monolith by a hydrothermal method. Compared to porous TiO 2 , CuS-sensitized porous TiO 2 (CuS-TiO 2 ), and CdS-sensitized porous TiO 2 (CdS-TiO 2 ) in terms of PEC performance, the CuS-CT photoanode exhibited a significantly high anodic photocurrent for water splitting under simulated sunlight radiation. The photocurrent produced by the optimized sample of 7% CuS-5% CdS-TiO 2 (7% CuS-CT) was nearly 2.7 times higher than that of pure porous TiO 2 at 1.0 V versus a reversible hydrogen electrode (RHE). Porous TiO 2 possesses large surface areas that can drive fast electrolyte transport and afford more surface reaction active sites. On the other hand, CuS and CdS quantum dots not only broaden the visible light absorption range, but also improve photoinduced electron-hole separation efficiency. The co-sensitized multi-nanostructures photoanodes lead to a remarkable and promising application in PEC water splitting reactions. [ABSTRACT FROM AUTHOR]

Efficient production of H 2 via solar-light-driven water splitting by a semiconductor-based photocatalyst without noble metals is crucial owing to increasingly severe global energy and environmental issues. However, many challenges, including the low efficiency of H 2 evolution, low solar light absorption, excited electron–hole pair recombination, and slow transport of photoexcited carriers, must be resolved to enhance the H 2 photoproduction efficiency and photocatalyst stability. Here, a two-step method is used to synthesize advanced H 2 -generating photocatalysts consisting of pyramid-like CdS nanoparticles grown on a porous TiO 2 monolith, which show promising photocatalytic activity for the hydrogen evolution reaction. Furthermore, the stability of the photocatalysts is examined through long-term tests to verify their good durability. Without noble metals as cocatalysts, the photocatalyst can reach a high H 2 production rate of 1048.7 μmol h −1 g −1 under UV–vis irradiation when the ratio of the CdS nanoparticles to TiO 2 is 5 mol%. This unusual photocatalytic activity arises from the wide-region light adsorption due to the narrow band gap of CdS, effective separation of electrons and holes due to conduction band alignment at the CdS–TiO 2 interface, and favorable reaction sites resulting from the porous structure. [ABSTRACT FROM AUTHOR]

• A strategy to quantify α phase strengthening in titanium alloys is proposed. • The interface-affected zone arising from spherical primary α grains is introduced. • Elastic interaction energy coupling by the semi-coherent interfaces of lamellae. • The orientation and growth direction affect the non-uniform strain in α lamellae. A strategy to quantify the second phase strengthening of α precipitates in titanium alloys is proposed to predict the mechanical performance through crystal plasticity finite element (CPFE) models. Considering the different dominant features of equiaxed and lamellar microstructures, statistical and microstructural factors are introduced to describe the slip resistance variations in the β matrix. The significant contribution of the interfaces is incorporated by introducing the interface-affected zone (IAZ) into crystal plasticity constitutive laws of equiaxed microstructures. In particular, the slip resistance variation is derived accounting for the interfacial energy distribution inside the IAZ. Meanwhile, the arrangement of the α lamellae is more compact and complex than that of spherical α grains in equiaxed microstructures; thus, instead of the IAZ, the interface length density is applied to describe the strengthening effects of the interfaces in lamellar microstructures. The elastic interaction energy induced by the semi-coherent interfaces of lamellae is obtained according to the micro-elastic theory. Using the advantages of the aforementioned improved models, CPFE simulations of the tensile behavior of equiaxed and lamellar microstructures at room temperature are performed, with the results matching well with the experimental data. Moreover, differences regarding the lattice structures and grain orientations lead to non-uniform strain partitioning in equiaxed and lamellar microstructures. Equiaxed α grains that favor prismatic slip tend to bear more plastic deformation than those favoring basal slip. The growth direction of α lamellae affects the deformation ability as well. Consequently, the proposed approach can precisely predict the mechanical properties of dual-phase titanium alloys through statistical values of microstructural features, and can be utilized in the investigations of other metals with similar structural characteristics. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: [•] Porous Sn/Nd-codoped TiO2 photocatalysts were synthesized. [•] The dopant can narrow band gap of TiO2 photocatalyst. [•] The dopant can prevent recombination of photogenerated carriers. [Copyright &y& Elsevier]