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This study describes a new strengthening technique that involves the combination of CFRP jackets, CFRP sheets and high- strength grouting material. Three different strengthening alternatives were employed to strengthen three severely damaged RC columns. Based on the experimental results, the failure mode, hysteresis curve, skeleton curve, ductility, energy dissipation ability, stiffness degradation and strength degradation of both the original and strengthened test specimens were compared and discussed. All three strengthened test specimens exhibited similar damaging processes, yielding of longitudinal reinforcement, cracks on CFRP jackets, rupture of CFRP sheets and collapse of high-strength grouting material were successively observed in the loading procedure. The results showed that the three strengthened seismic damaged concrete columns all presented a bending failure mode and met the “strong shear, weak bending” design attributes. Compared with the original columns, the ductility and energy dissipation capacity of the three strengthened test specimens were significantly improved, while the capacity and stiffness were not fully restored. Strengthened test specimen Z3-R, which was strengthened by the combination of CFRP jackets, CFRP sheets and high-strength grouting material, showed the best seismic performance among all three strengthened test specimens. A finite element model based on OpenSees was developed and validated by a comparison with experimental results. The effects of the axial compression ratio and thickness of CFRP sheets were also discussed through parametric studies.

The hydrolysis process and mechanisms of unique as-prepared KCrO2 and K3CrO4 were systematically investigated. The characterization results of XRD, IR and SEM show that the hydrolysis reaction can be realized at a low reaction temperature of 80 °C and a reaction time of 24 h. Moreover, the greyish-green α-CrOOH with a hexagonal plate-like morphology and a large size of 10 μm is formed via the hydrolysis of the single-phase hexagonal KCrO2, while the green sol−gel of amorphous Cr(OH)3 with a lumpy aggregate morphology is generated through the hydrolysis of a cubic K3CrO4. It is a facile and rapid method to synthesize pure-phase chromium oxyhydroxide via the above hydrolysis.

In this work, iron-based metal organic frameworks (Fe-MOF) are used as a self-sacrifice beacon to produce Prussian blue (PB). Then, a dual-mode electrochemical-colorimetric biosensing platform for kanamycin (KAN) detection is established considering the prominent redox activity and blue color of PB. CoFe

Effective seismic properties are a basic requirement in precast shear wall applications. Therefore, this study focuses on the evaluation and improvement of precast shear wall seismic properties using the new pore-forming grouted connector with welded closure confinement steels (NPGCS) developed in previous research. The NPGCS connector reliability was verified and the seismic properties of the NPGCS spatial structure model were evaluated by carrying out a low cyclic reversed lateral loads experimental test on the NPGCS precast shear wall spatial structure model containing superposed connecting beams and precast shear walls, which were selected from a practical high-rise precast residential building. According to the testing results of the crack distribution and component failure modes, the superposed connecting beam properties were weak, and damaged early in the shear failure mode, while the precast shear walls cracked after the steel bars in the superposed connecting beams yielded. Furthermore, the failure mode indicated that the NPGCS connection applied in this spatial model is reliable, while two new weak sections were proven to exist at the connector ends. Together with the precast joint interface slip, the dowel shear action is demonstrated to be harmful to the joint interface properties. Additional seismic parameters, namely capacity, ductility, stiffness and energy consumption, were used to complete the evaluation of the seismic properties of the NPGCS spatial structure model. Overall, although the NPGCS spatial model ductility is low, the strengths are high, leading to continued effective energy consumption properties, which indicates favourable seismic properties of the NPGCS spatial structural model.

An unbonded post-tensioned (PT) concrete wall system with vertical energy-dissipating connections (UPTW-VEC) is proposed that consists of precast wall panels, several X-shaped metal dampers (XMD), mild steel energy-dissipating bars (ED bars) and PT tendons. In this wall system, the precast wall panels are assembled through XMDs along the vertical joints and ED bars along the horizonal joints to provide the energy-dissipating capacity. The PT tendons installed at the wall toes are used to provide the self-centering capacity. In addition, each wall toe is protected by a steel jacket from the concrete corners spalling or crushing. Firstly, the hysteretic behavior of XMD was studied experimentally. Then, the seismic behavior of the unbonded post-tensioning concrete wall with different parameters were investigated experimentally based on four specimens. It was shown that the wall panels were resilient after tests and the cracks were only observed near the embedded plate in wall panels. In addition, a simplified analysis method was proposed, and the theoretical results matched well with the experimental results. Finally, the finite element analysis (FEA) model of UPTW-VEC was established. Following validating through the experimental results, a parametric study was conducted to investigate the influence of critical parameters on the seismic behavior of UPTW-VEC.

A novel developed lapping connection between concrete-filled rectangular steel tubular (CFRST) columns and reinforced concrete (RC) beams was introduced in this paper. In this new connection system, the longitudinal reinforcements of RC beams were interrupted so the steel tubular column can be continuous in the joint zone. The longitudinal reinforcements were lapped with the steel brackets, which were welded with the steel tubular column, to effectively transfer the moments and shear forces and reduce welding operation on site. The seismic performance of this newly connection was investigated through combination of theoretical research, experimental tests and finite element model analysis. Design methods of each part of the connection were proposed. Moreover, four beam-column connection specimens were tested under combined constant axial compression and cyclic loading. Based on the experimental results, the failure modes, hysteretic response, skeletal curve and ductility were discussed. The connection demonstrated favorable seismic performance in the tests and the capacity of connection characterized as beam bending failure mode was consistent with the theoretical results. A finite element model was developed and validated by a comparison with experimental results. The relative effects of the beam-column strength ratio kM on failure modes of the joints were conducted. Three typical failure modes which were beam bending failure mode, bending-shear mixed failure mode and joint shear failure mode as well as the discriminant k M D between different failure modes were determined. Theoretical results well agreed with the analytical results under joint shear failure mode, and bending failure mode with relatively inferior kM.

The real time pH monitoring is crucial for human body health and environmental protection. In this work, a triphenylamine-conjugated TPA-SA (triphenylamine (TPA) and salicylaldehyde (SA)) with ESIPT segment was successfully designed, synthesized and further applied in pH detection bearing larger Stoke shift. Optical properties indicated that the sensor TPA-SA displayed obvious AIE (aggregation induced emission) phenomenon in DMSO/H2O (1/1, v/v) mixed solution, nano-scaled granular-like aggregates of TPA-SA could be obtained through scanning electron microscope images (SEM) and dynamic light scattering (DLS). It was worth mentioning that TPA-SA showed excellent fluorescence reaction to changes in pH, and pKa was calculated to be 4.75. In addition, due to its special optical properties, the further practical application of sensor TPA-SA was successfully conducted in pH sensing strips, information storage and the fluorescence cell imaging in HeLa cells, which may be commercially used in near further.

Due to the carcinogenicity of atrazine, the effective removal of atrazine in water and soil has become the focus of attention. In the paper, the advanced oxidation technology based on sulfate radicals ( S O 4 · - ), which the visible light catalysis and nanocatalyst Co3O4/g-C3N4 synergistically catalyzed to yield S O 4 · - , was constructed to efficiently degrade and remove atrazine. The Co3O4/g-C3N4 was prepared through a simple solvothermal method, and its microstructure and composition were characterized by SEM and XRD. A series of experiments were carried out to degrade atrazine by Co3O4/g-C3N4 activation of peroxymonosulfate under visible light, which revealed that the degradation efficiency reached to 78.5 percent in 35 min, CO32− had a significant inhibitory effect on the degradation of atrazine in coexisting ions of NO3-, SO42−, Cl- and CO32−, the e-, ⋅OH, and S O 4 · - were mainly active species. Combined with density function theory calculations of Co3O4/g-C3N4, the high-efficiency degradation of atrazine was due to the synergetic enhancement between photocatalysis and Co3O4/g-C3N4 catalyst in the constructed catalytic system.

Discretely connected precast reinforced concrete floor diaphragm (DCPCD) is a new-type untopped precast concrete floor system. Using slab joint connectors, instead of cast-in-situ concrete overlap layers on precast slab, to transmit slab joints inner forces caused by vertical and horizontal loads eliminates the need for wet works in construction site, thus leading to economical designs and high efficiency in installation. This paper presents the development and experimental evaluation of DCPCD subjected to in-plane low-cyclic reversed loading. Performance of the tested specimen was evaluated in terms of failure mode, in-plane deformation pattern, hysteretic curves, stiffness, ductility and energy dissipation capacity. The results show that DCPCD had high in-plane stiffness and good integrity, and the beam-to-slab connections and slab joints perform well during the test process. The ductility of the specimen is acceptable, while the energy dissipation is not that satisfactory, confirming that the elastic design method of precast RC diaphragms is rational. The shear and axial force distribution regularity of the tested specimen was analyzed, and the results indicate that internal force distribution is similar to that of the simply supported beam. The equivalent beam model theory was modified based on the measured tensile (compressive) stiffness of slab joint connectors and the actual load effect in the floor et al. It is demonstrated that the in-plane deformations determined by the modified calculation method agree well with the test results. Hence, the proposed in-plane stiffness analysis method is reliable and can be used for designing buildings adopting DCPCD.

In this study, Cr2O3 green pigments were prepared using two types of CrOOH, alpha-CrOOH and gamma-CrOOH, and the resulting pigments were characterised. The thermal decomposition behaviours of the two types of synthesised CrOOH were discussed. The resulting Cr2O3 pigments were characterised using X-ray diffraction (XRD), scanning electron microscope (SEM), International Commission on Illumination (CIE-L*a*b*) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). The key factors and mechanism that influenced the preparation of the Cr2O3 green pigments were studied. The results revealed that gamma-CrOOH produces Cr2O3 that is more homogeneous, has a uniform size of 200-400 nm and a yellowish-green colour compared to alpha-CrOOH, which produces Cr2O3 with non-uniform sizes and a brownish-green colour. In addition to the different particle morphologies and sizes, the change in the crystal field, which leads to a shift in the (4)A(2g) -> T-4(1g) and (4)A(2g) -> T-2(2g) transition, also affects the colour of the pigment. Lastly, a series of Cr2O3 green pigments displaying a wide range of colours were prepared by calcining mixtures of alpha-CrOOH and gamma-CrOOH with different compositions. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Cr2O3 green pigment was prepared through the thermal decomposition of chromium hydroxide precursor, which was precipitated by Cr(NO3)(3) and NaOH solutions. The color performance of as-prepared Cr2O3 is comparable to the commercial pigment when the precursor was precipitated from 025 mol/L Cr(NO3)(3) solution. When increasing the concentration of Cr(NO3)(3) solution, the color of Cr2O3 becomes more reddish and much darker. The structure and morphology of different precursors and Cr2O3 samples were characterized. Amorphous precursor with non-agglomerated particles, which could be obtained by controlling the concentration of Cr(NO3)(3) solution, was found to be a prerequisite for preparing Cr2O3 pigment with good color performance. (C) 2013 Elsevier B.V. All rights reserved

In order to reduce greenhouse gas emission and urban heat island mitigation, pure and titanium(Ti)-doped Cr 2 O 3 cool pigments were prepared via the thermal decomposition of CrOOH. The result reveals that the pure Cr 2 O 3 pigment presents both a high near-infrared reflectance and excellent yellowish-green color. Meanwhile, titanium was doped to improve the NIR reflectance and strengthen the color. The color of the designed pigments was brighter, and most importantly, the NIR reflectance increased from 84.04% to 91.25% with increasing Ti content from 0 to 0.006% (mole fraction). However, excessive doping of Ti 4+ for Cr 3+ in Cr 2 O 3 ( x (Ti)≤0.008%) decreased the NIR reflectance. One possible reason is that the conductivity type of the Cr 2− x Ti x O 3+ δ changed from p-type conduction to n-type conduction with increasing Ti content, accompanied by the change of the electrical resistivity and the NIR reflectance. The prepared yellowish-green Cr 2 O 3 pigments have a great potential for extensive applications in construction and military.