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To ensure the safety of a falsework during the concrete pouring period, based on the reliability theory, a probabilistic limit state design method considering joint lap defects was proposed. The representative construction sites were selected for field investigation. The occurrence rules and the statistical characteristics of the joint lap defects in the false-work were obtained. The joint lap defects were simulated numerically. The influence of the construction load and the number of the false-work spans on the load effect coefficient was analyzed. The probabilistic limit state design expressions with and without joint lap defects were established, respectively, and the results were compared with the reliability index obtained by the technical code for safety steel tubular scaffold with couplers in construction. The results show that the nonlinear finite element model has high accuracy in simulating joint lap defects. The influence of the construction load on the load effect coefficient is far greater than that of the number of the falsework spans. The reliability index obtained by the proposed de sign method has the best consistency with the target reliability index. [ABSTRACT FROM AUTHOR]

Background: Faced with the challenge of population aging, a prolonged working life is increasingly important in today's society. Maintaining work ability of employees is one of the effective ways to cope with the challenges to sustainability of the workforce presented by population aging. Researchers have shown ongoing interest in exploring the determinants of restricted work ability. The aim of this study was to evaluate the effects of work stress on work ability among power supply workers in Guangdong, China.Methods: A cross-sectional study was conducted among power supply workers during August 2014 to September 2014. A total of 805 subjects were enrolled in the study. Work stress was assessed by the Job Content Questionnaire and the Effort Reward Imbalance Questionnaire. Work ability was assessed by the Work Ability Index (WAI). The structural equation model was applied to test the relationship between different work stress components and work ability simultaneously using the Job Demands-Resources model as a framework.Results: Job resources (measured by job control, reward and social support) were positively and directly associated with work ability (β = 0.70, P < 0.001). The association between job demands and work ability was also statistically significant (β = -0.09, P = 0.030). In addition, the findings also supported previous studies in that job demands were correlated with job resources (β = -0.26, P < 0.001).Conclusions: Our findings suggest that decision makers and health care providers should consider increasing job resources available to power supply workers. Consideration of organizational changes related to the design of the job task also would be useful to improve the employees' work ability. [ABSTRACT FROM AUTHOR]

Controllablesynthesis of graphite oxide (GO) for targeted surface properties isof great importance for its versatile applications. For this purpose,GO samples were prepared with different amounts of oxidant and characterizedby X-ray diffraction, Fourier transform infrared spectroscopy, 13C cross-polarization with total sideband suppression magic-angle-spinningnuclear magnetic resonance, X-ray photoelectron spectroscopy, Ramanspectroscopy, and ζ-potential measurement. When the oxidantamount is below a critical value, the epoxy groups are dominant onthe GO surfaces, together with a few hydroxyl and carbonyl groups.Further increase in the oxidant amount leads to the formation anddevelopment of the carboxyl groups, which eventually reach a saturationlevel. Meanwhile, the increasing oxygen-containing groups introducemore defects and reduce the crystalline graphene domains on GO. Apossible mechanism for the formation of the oxygen-containing groupson GO is proposed, providing a guideline for the manipulation of theGO surface properties. [ABSTRACT FROM AUTHOR]

• An innovative interfacial solar-thermal material Cu@Bi2WO6-C is developed. • No significant salt deposition on the material surface during seawater evaporation. • High evaporation rate of 2.07 kg m−2h−1 and evaporation efficiency of 97 % are obtained. • The outdoor evaporation device demonstrates the availability in long-term desalination. Photothermal evaporation is an efficient way to utilize solar energy to desalinate seawater for freshwater resources, which can effectively alleviate the press on accessing to freshwater in water-scarce countries and regions. Here, a highly efficient ternary composite consisting of Bi 2 WO 6 , copper and carbon is developed as a photothermal conversion material for solar-driven water evaporation (SDWE) systems. This composite is coated on the top of a base consisting of expanded polystyrene (EPS) foam and hydrophilic fiber paper to construct an interface evaporator, enabling sustainable solar-driven freshwater production. Due to its wide light absorbing range, localized photothermal conversion and low evaporation enthalpy, the solar steam generation (SSG) through Cu@Bi 2 WO 6 -based evaporator could be accelerated, thus a high evaporation rate of 2.07 kg m−2 h−1 and an evaporation efficiency of 97 % are obtained under one sun, outperforming the-state-of-art evaporators. This work proposes a feasible way to deal with freshwater shortage. [ABSTRACT FROM AUTHOR]

[Display omitted] As the most promising anodes for Na+/K+ batteries (SIBs/PIBs), transitional metal sulfides present the advantages of high capacity, straightforwardly-controlled morphology and abundant redox reaction sites. However, maintaining the structural integrity of the electrode materials during cycling and improving the cycle life still face great challenges. Herein, CoS 2 @NPSC@MoS 2 nano-spindle heterostructure with multiple heteroatoms co-doped carbon layers coupled with Janus metal sulfides (CoS 2 and MoS 2) were successfully fabricated via the successive organic coating, gas-phase phosphorization and the final hydrothermal reaction processes. Benefiting from the uniformly dispersed CoS 2 nanocrystals in the interior of carbon layer and the MoS 2 nanosheets arrays in the exterior, Na+/K+ diffusion distances are remarkedly shortened and the reaction kinetics are greatly improved, which also provide more active sites on the surface for exposure to the electrolyte. The presence of heterogeneous atomic N/P/S co-doped carbon layer greatly improves the electrochemical conductivity of the heterostructure and provide additional buffer space for volume changes, which is conducive to retaining the integrity of the electrode structure during the cycling processes. When used as the anode material for SIBs/PIBs, it reached the reversible specific capacity of 340.44 mAh g−1 at 5.0 A g−1 after 1000 cycles for SIBs and 37.53 mAh g−1 at 5.0 A g−1 after 800 cycles for PIBs. This work demonstrates a reliable and simple strategy for the rational design of Janus metal sulfides heterostructures for high performance Na+/K+ storage application. [ABSTRACT FROM AUTHOR]

Size effect of Pt nanoparticle (NPs) on electrocatalysis should be investigated in a wide size range and a narrow distribution. The surfactants used for size control were detrimental to exploring size effect. However, the largest size of Pt colloidal NPs was limited to ∼5 nm without surfactant, which is insufficient for investigating size effect. In this work, surfactant-free Pt colloidal NPs with a wider size range from 1.8 to 10.0 nm were synthesized by controlling the ratio of NaOH and Pt salts in the ethylene glycol by oil-bath heating. Assisted by the precise control of Pt size, the size effect on the electrooxidation of CO, methanol and ethanol was studied, showing that the optimal size varied from the specific catalytic reaction. The synthesis extended the upper limit of large Pt NPs by surfactant-free method, showing potentials in preparing other precious metal NPs with a wide size range. [Display omitted] • Wide size range synthesis of surfactant-free colloidal Pt nanoparticles in alkaline ethylene glycol. • Water accelerates the rate of particle formation. • Temperature increases the conversion of Pt precursor rather than the size. • The wide range is sufficient to study size effect on electrocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] Herein, heterogeneous bimetallic sulfides Bi 2 S 3 /Mo 7 S 8 nanoparticles anchored on MXene (Ti 3 C 2 T x) nanosheets (MXene@Bi 2 S 3 /Mo 7 S 8) were prepared through a solvothermal process and subsequent chemical vapor deposition process. Benefiting from the heterogeneous structure between Bi 2 S 3 and Mo 7 S 8 and the high conductivity of the Ti 3 C 2 T x nanosheets, the Na+ diffusion barrier and charge transfer resistance of this electrode are effectively decreased. Simultaneously, the hierarchical architectures of Bi 2 S 3 /Mo 7 S 8 and Ti 3 C 2 T x not only effectively inhibit the re-stacking of MXene and the agglomeration of bimetallic sulfides nanoparticles, but also dramatically relieve the volume expansion during the periodic charge/discharge processes. As a result, the MXene@Bi 2 S 3 /Mo 7 S 8 heterostructure demonstrated remarkable rate capability (474.9 mAh/g at 5.0 A/g) and outstanding cycling stability (427.3 mAh/g after 1400 cycles at 1.0 A/g) for sodium ion battery. The Na+ storage mechanism and the multiple-step phase transition in the heterostructures are further clarified by the ex-situ XRD and XPS characterizations. This study paves a new way to design and exploit conversion/alloying type anodes of sodium ion batteries with hierarchical heterogeneous architecture and high-performance electrochemical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • N -doped carbon coated nickel (Ni@NC) is prepared for electrochemical CO 2 reduction (ECRR). • There is a synergistic effect between Ni and N to ECRR activity. • The effect of pickling on ECRR performance of Ni@NC is revealed. • The adsorbed Cl on Ni@NC surface after pickling improves the ECRR performance. • The origin of the activity and selectivity of the pickling Ni@NC for ECRR is elucidated. Converting CO 2 into valuable chemicals and fuels through clean and renewable energy electricity provides a way to achieve sustainable development for human societies. In this study, carbon coated nickel catalysts (Ni@NCT) were prepared by solvothermal and high-temperature pyrolysis methods. A series of Ni@NC-X catalysts were obtained by pickling with different kinds of acids for electrochemical CO 2 reduction reaction (ECRR). The results show that Ni@NC-N treated with nitric acid has the highest selectivity but lower activity, Ni@NC-S treated with sulfuric acid has the lowest selectivity, and Ni@NC-Cl treated with hydrochloric acid shows the best activity and good selectivity. At –1.16 V, Ni@NC-Cl has a considerable CO yield of 472.9 μmol h−1 cm−2, which is significantly superior to Ni@NC-N (327.5), Ni@NC-S (295.6) and Ni@NC (270.8). The controlled experiments show that there is a synergistic effect between Ni and N. The chlorine adsorbed on the surface can promote the performance of ECRR. The poisoning experiments indicate that the contribution of surface Ni atoms to the ECRR is very small, and the increase of activity is mainly due to the nitrogen doped carbon coated Ni particles. The relationship between activity and selectivity of ECRR on different acid-washed catalysts was correlated by theoretical calculations for the first time, which is also in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biomimetic hygro-actuated wooden building systems are reviewed. • Key to the hygroscopic actuation is the chemical and structural variations between bi-layers. • Typical hygro-actuated systems include self-shaping structures, smart ventilations, motor and self-propelling robot. • Existing issues and challenges in applying industrially the hygro-actuated building systems are given. Hygroscopic movement is widely observed in plant and is a self-shaping response that does not require an external force or energy. It is interpreted as the adaptation capability of plants to their environments. The key to the hygroscopic movement is the structural arrangement of the plant tissues, typically in a bi-layer configuration. Herein, the transfer from the principles of hygroscopic movement of plants to biomimetic wooden building systems is reviewed. Biomimetic wooden building systems have been generated from the centimeter- to meter-scale, such as "silenced tower", smart ventilations, and self-propelling robots. However, achieving programmed and precise shape changes on an appropriate time scale is challenging. For example, almost all currently available hygro-actuated composites are inferior to the pine cone scales, which can be conducted many opening-closing cycles without fatigue failure. Therefore, an optimized configuration of the biomimetic composites is necessary to improve their durability by fully understanding of the plants structures. Enhancing the applicability among the common wood species worldwide is also challenging when promoting hygro-actuated composites in industrial applications. Furthermore, finding an appropriate trade-off between response time and mechanical stability of the composites is essential when reacting to changing environmental stimuli. Over-all, the cross-disciplinary studies between plant biology and engineering provide solutions for fabricating sustainable and energy-saving smart building systems. [ABSTRACT FROM AUTHOR]