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This article describes the design and characterization of CuInS2-based core–multishell nanocrystals with the appropriate architecture of MnS as the inner layer and ZnS as the outer layer. These are wider bandgap materials being used to develop the type-I core/shell structure. The designed CuInS2/MnS/ZnS colloidal nanocrystals were synthesized by a multistep hot-injection method. This material gains importance in view of its superior luminescence property. The existence of an efficient dual emission in both green and NIR regions, with high stability corresponding to 543 and 752 nm, highlights its utility as an efficient bioimaging probe, and its formation was confirmed with combined optical and structural characterization techniques. The photoluminscence study revealed that the optimum concentration of both shells was 0.1 mmol (by varying shell concentration from 0.1 to 0.5 mmol), since beyond this concentration the intensity of the shells was reduced gradually according to the concentration. The zinc blende structure was retained throughout the entire growth process with slight deviation in the diffraction peak positions. The oxidation states of the elements present in the system were confirmed by X-ray photoelectron spectroscopy studies. High resolution transmission electron microscopy observation confirmed multiple layers in the synthesized material. The prepared nanocrystals are made hydrophilic by encapsulation with F127 copolymer, and their cell viability studies revealed the material to be of negligible cytotoxicity. All together, the study strongly suggests that the green and NIR emitting CuInS2/MnS/ZnS core–multishell nanocrystal, designed and synthesized in this study, is an attractive candidate as a biological contrast agent.

AbstractThis paper has utilised a comprehensive numerical investigation to assess the load distribution factors of steel–concrete composite box and I-girder bridges when subjected to different international bridge design loading configurations such as Australian Bridge Design Code and American Association of State Highway and Transportation Officials (AASHTO). In this study, the effect of different parameters such as span length, number of loading lanes and number of cells/girders are investigated. Different types of elements such as solid element, shell element and beam element are examined to find a suitable finite element model to accurately simulate the components of these bridge structures. The accuracy of the finite element models is confirmed with available experimental results. A large number of results are produced by varying the values of the different parameters which are used to determine the load distribution factors for bending moment and shear force of box and I-girder bridges. Design guidelines in the form of empirical expressions for the load distribution factors are also derived from this big database.

AbstractThis paper presents a comprehensive numerical investigation using finite element analysis to assess the load carrying capacity of prestressed skewed bridges using Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) subjected to Australian bridge load configurations. A preliminary study is performed on different types of prestressing modelling techniques to find a suitable mechanism for accurately representing the prestressing force in the bridge structure models. To ensure the accuracy of the modelling methods, the results obtained from this analysis are validated with experimental results. A parametric study is also carried out to investigate the effect of skew angle, UHPFRC strength and the ratio of span width to normal length. It is concluded that UHPFRC material can be fully or partially incorporated into a bridge structure resulting in slender sections thus saving in the concrete quantity, reinforcement and achieving longer spans that are not feasible using the normal concrete.

Carbonylative coupling of phenylethyne with 4-methoxy-1-iodobenzene in the presence of 1 mol % PdCl2(PPh3)2, 2 equiv of 0.5 M aqueous ammonia, and CO (1 atm) gives the corresponding α,β-alkynyl ketone in 72% isolated yield after stirring at room temperature for 41 h, while noncarbonylative coupling product is not obtained.

A major design consideration for gluing steel plates to reinforced concrete beams and slabs is the prevention of premature debonding of the plate. Once debonding is prevented, then standard linear elastic theory or rigid plastic analysis techniques can be applied. This review describes the gains in strength and stiffness that have been achieved by plating, the different forms of debonding that have been encountered experimentally, the parameters that affect these debonding mechanisms, and the mathematical models that have been developed in an attempt to prevent premature debonding.

Four-component coupling of a terminal alkyne, hydrazine (hydroxylamine), carbon monoxide, and an aryl iodide furnishes pyrazole or isoxazole derivatives in the presence of a palladium catalyst. The reaction proceeds at room temperature and an ambient pressure of carbon monoxide in an aqueous solvent system.