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Traditional sacrificial concrete retaining blocks (CRBs) play a significant role in reducing the excessive transverse displacements of bridge superstructures and protecting the substructures from severe damage during seismic events. However, rehabilitating these CRBs after earthquakes is very difficult. Thus, many previous studies proposed the prefabricated retaining blocks (PRBs) with the unbonded post-tensioned prestressing tendons (PTs), which has been proven to be effective in maintaining the same functionality as that of traditional sacrificial CRBs while also simplifying their postearthquake rehabilitation. However, the response mechanisms and influential parameters of the abutment PRB under the horizontal seismic loads are unclear, affecting its further application in practical bridge engineering. This study established the three-dimensional (3D) finite-element (FE) model of the abutment PRB designed by the previous researcher and validated the feasibility and effectiveness of studying its seismic behavior through the available experimental results. Additionally, comprehensive parametric studies were performed to examine the effects of the friction coefficients, initial tension forces, and tensile strength of PTs on the seismic behavior of the abutment PRB. Subsequently, to fully utilize the mechanical merits of ultrahigh-performance concrete (UHPC), this paper proposed the modified abutment UHPC-PRB structures and their hysteretic behavior and damage modes were compared with those of the original ones through numerical simulations and available test results in the literature. Finally, the results indicated that (1) the developed FE models could accurately simulate the seismic behavior of the abutment PRBs; (2) the friction effect between the PRB body and side surface of the abutment stem wall had significant impacts on the hysteretic behavior and energy-dissipation performance of the abutment PRBs; (3) the critical rotational load, horizontal loading strength, deformation ability, energy-dissipation ability, and self-resetting capacity of the abutment PRBs could be improved with the increase of the initial tension force and tensile strength of PTs; and (4) the proposed replaceable abutment UHPC-PRB structures exhibited superior seismic performance and outperformed mechanical merits compared to traditional sacrificial CRBs. [ABSTRACT FROM AUTHOR]

AbstractSeeking new modification adsorbents of graphene oxide with high uptake for some heavy metal ions is still the current hot-pot in adsorption technique. An amino-silanized and thiosemicarbazide modified graphene oxide adsorbent (TSCGO) was synthesized by silanized and crosslinking reaction of graphene oxide. The structure, morphology and thermostability of TSCGO were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and BET methods. The characteristic results verified that TSCGO was successfully acquired. The adsorption experiments of TSCGO for Hg2+, Pb2+, Cd2+, Zn2+ and Cu2+ showed that TSCGO owned higher uptake for Hg2+ and Pb2+ than the other ions. Main factors affecting adsorption of TSCGO for Hg2+ and Pb2+ were analyzed. The adsorption kinetics was studied using pseudo-first-order, pseudo-second-order, Elovich, Boyd, Weber and Morris models. The adsorption followed the pseudo-second-order kinetic and Weber and Morris intraparticle diffusion models. The adsorption isotherms were fitted using Langmuir, Freundlich, Temkin, Redlich-Peterson and Hill models. The best isothermal models should be Hill model for Hg2+ and Redlich-Peterson model for Pb2+. The maximum uptakes of Hg2+ and Pb2+ obtained from the Hill model were 933.2 and 890.4 mg g−1, respectively, which were much higher than those of some reported adsorbents from the Langmuir model. The adsorption of TSCGO for Hg2+ and Pb2+ was an endothermic and spontaneous chemical process. TSCGO could be effectively regenerated with EDTA. Hence, TSCGO would be a promising adsorbent for removal of Hg2+ and Pb2+ from wastewaters. [ABSTRACT FROM AUTHOR]

Highlights: An efficient moist-electric generator with ultra-fast electric response to moisture is achieved by triggering Grotthuss protons hopping in the moisture-electric–moisture-sensitive heterostructure. The moist-electric generator produces a quick response (0.435 s), an unprecedented ultra-fast response rate of 972.4 mV s−1 to alternating moisture stimulation and stable output for 8 h. An obstructive sleep apnea hypoventilation syndrome diagnostic system based on a moist-electric generator was developed to monitor hypopnea and apnea in real time and successfully diagnose them with early warning. Moisture-enabled electricity (ME) is a method of converting the potential energy of water in the external environment into electrical energy through the interaction of functional materials with water molecules and can be directly applied to energy harvesting and signal expression. However, ME can be unreliable in numerous applications due to its sluggish response to moisture, thus sacrificing the value of fast energy harvesting and highly accurate information representation. Here, by constructing a moisture-electric–moisture-sensitive (ME-MS) heterostructure, we develop an efficient ME generator with ultra-fast electric response to moisture achieved by triggering Grotthuss protons hopping in the sensitized ZnO, which modulates the heterostructure built-in interfacial potential, enables quick response (0.435 s), an unprecedented ultra-fast response rate of 972.4 mV s−1, and a durable electrical signal output for 8 h without any attenuation. Our research provides an efficient way to generate electricity and important insight for a deeper understanding of the mechanisms of moisture-generated carrier migration in ME generator, which has a more comprehensive working scene and can serve as a typical model for human health monitoring and smart medical electronics design. [ABSTRACT FROM AUTHOR]

The geometries, electronic structures, and spectral properties of three metal complexes Zn(C10H12N3OS)2 (1), Ni(C10H12N3OS)2 (2), and Pd(C10H12N3OS)2 (3) with N-(2-pyridinyl)morpholine-4-carbothioamide as a ligand are investigated by means of DFT (density functional theory) and TD-DFT (time-dependent density functional theory) methods. Complex 1 is a distorted tetrahedral geometry, while complexes 2 and 3 present a distorted square-planar coordination environment. In the simulated range, the spectrum of complex 1 has five obvious absorption peaks and one of them has the strongest intensity. The latter two complexes have one more absorption peak and shoulder peak with the similar intensity. Moreover, the strongest peaks of complexes 2.