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In this study, at first a NNN pincer type ligand was synthesized through the nucleophilic substitution reaction of 2,2′-dipyridylamine with trichloro-1,3,5-triazine in 2:1 ratio. In the next step, the magnetic chitosan biosupport was reacted with this nitrogen-rich ligand that provided coordinative sites for the palladium complexation. The prepared nanocomposite (Fe3O4@DPA-CS@NNN-Pd0) was identified by different analysis including FT-IR, XRD, EDX, FESEM, DLS, VSM and ICP. Then, its catalytic activity was examined in the Sonogashira coupling reaction. The related products were produced in a short reaction time with proper yields. Moreover, the nanocatalyst can be magnetically separated and reused for four successive runs with no noticeable loss in its catalytic activity. [ABSTRACT FROM AUTHOR]

Traffic signals and information signs play a vivid role in maintaining safe travel by guiding drivers on highways and urban roads. Traffic mast arm structures are susceptible to vibrations induced by wind loads. Fatigue-induced failure is common in these structures. However, it is crucial to ascertain the functionality of signal support structures. This paper lays the foundation for a fully computational framework to model and mitigate wind-induced vibrations in traffic lighting support structures by conducting computational fluid dynamics (CFD) simulations, dynamic modeling, and damping enhancement. We validated the CFD simulations by aerodynamic testing. The dependence of flow pattern and aerodynamic loads on Reynolds number reveals the importance of full-scale CFD with large eddy simulation for wind load estimation on mast arm structures. Distributed tuned mass dampers were created by employing available weights of lighting boxes. The results show that distributed tuned lighting boxes are effective for vibration suppression. Besides, damping enhancement can significantly reduce vibration-induced stresses and hence extend the fatigue life. The proposed mitigation technique promises to save construction costs and improve the safety of the traveling public. The procedure followed for creating time histories of wind loads integrated with finite element modeling applies to other vibration lessening techniques for potential inclusion in the AASHTO standard. [ABSTRACT FROM AUTHOR]

In the current study, thermal–hydraulic characteristics of nitrogen gas–water two-phase flow through a plate–pin fin heat sink are investigated experimentally. Water flow through the smooth case, i.e., heat sink without pin fin, is considered as baseline. Four new models of the pin fin with variable longitudinal pitch and pin length having low-to-high and high-to-low arrangements are proposed. They are named for short as LP–LH, LP–HL, PL–LH, and PL–HL. The results indicate that in all heat sinks, the Nusselt number values of the two-phase flow in comparison with those of the single-phase flow are higher, but the friction factor values of the two-phase flow in comparison with those of the single-phase flow are lower. Also, the friction factor and the Nusselt number of both the single-phase flow and the two-phase flow in the heat sinks with pin fin are greater than those in the heat sink without pin fin. The highest values of the Nusselt number are recorded for PL–HL at water mass flow rate of 0.0093 kg s−1 and gas volume flow rate of 0.8 L min−1. At these flow rates in PL–HL, the Nusselt number of the two-phase flow is increased about 45.6% relative to the single-phase flow. [ABSTRACT FROM AUTHOR]

In previous studies, the mechanical behavior of a micro-tweezer with homogenous and the same material has been investigated. In this paper considering the desired characteristics of FGMs, as a good thermal and wear resistance, the mechanical behavior of FGM micro-tweezer under DC voltage and temperature variations is investigated. It is assumed that the two micro-beams of the FGM micro-tweezer are mounted symmetrically against each other and one side of the micro-beams is made of a pure metal the other side is a mixture of metal and ceramic, and the percentage of ceramic varies exponentially through the micro-beams thickness. The nonlinear equations governing the static deflection of micro-beams due to the application of DC voltage and the temperature changes are derived and solved using the step by step linearization method and the Galerkin method. The response and the stability of the system against the variation of DC voltage and temperature are investigated. Also, the effect of geometrical dimensions, ceramic percentage and its variations through the micro-beams thickness on the mechanical behavior and the system stability are studied. [ABSTRACT FROM AUTHOR]

This paper presents an integrated decision support system (DSS) for performance assessment of decision-making units. The integrated DSS (AutoAssess) is developed by C# in .NET environment and is capable of identifying weak and strong points as well as providing basic assessment tools for performance analysis of decision-making units. The structure of AutoAssess is based on fuzzy data envelopment analysis, principle component analysis (PCA), data envelopment analysis (DEA), numerical taxonomy (NT), and Spearman correlation experiment. NT and Spearman correlation experiment are used as verification and validation tools. AutoAssess requires users to provide standard numerical values for inputs, outputs, and indicators through standard pop-up menus or built-in spreadsheets. The integrated mechanism of AutoAssess can help managers to continuously identify relative assessment of their units with respect to others. AutoAssess is the first integrated DSS capable of performing various DEA models, PCA and numerical taxonomy analysis. The integrated DSS is developed and tested by the ISO-International Electrotechnical Commission usability design features. Also, its advantages over existing software (such as Lindo, DEA Excel Solver, Frontier Analyst, SPSS, and MathCAD) are examined through qualitative and quantitative assessments. [ABSTRACT FROM AUTHOR]

In this paper, dynamic simulation of a beam-like structure with a transverse open crack subjected to a random moving mass oscillator is investigated. The simultaneous effect of a crack and a random oscillator has not been addressed up to now. The crack in the beam at different locations and with different depths is considered as one group of damage, each as an individual imperfection. In addition, bearing immobility is considered as another type of problem in the beam. Mass, stiffness, damping and velocity of the oscillator are assumed to be random parameters. An improved perturbation technique is applied to reduce the simulation time. It was found that there is a maximum value of the variance of each uncertain parameter, in which the maximum reliability of the perturbation method can be achieved, and that this maximum value can be obtained by the Alpha-Hilber Monte-Carlo simulation method. The simulation results reveal that the mass and the velocity uncertainty cause high uncertainty in the deflection of the beam. Also, the pattern of the deflection is not affected by different random oscillator parameters, and as a result, the type of damage can be identified even with high uncertainty. Moreover, the deflection in the nodes around the mid-span of the beam provides the best information regarding the imperfections, and consequently leads to the best sensor locations in an actual experiment. [ABSTRACT FROM AUTHOR]

Assembly line balancing often has significant impact on performance of manufacturing systems, and is usually a multiple-objective problem. Neither an algorithmic nor a procedural assembly line balancing methodology is usually effective in solving these problems. This article proposes a data envelopment analysis (DEA) approach to solve an assembly line balancing problem. A computer-aided assembly line balancing tool as Flexible Line Balancing software is used to generate a considerable number of solutions alternatives as well as to generate quantitative decision-making unit outputs. The quantitative performance measures were considered in this article. Then DEA was used to solve the multiple-objective assembly line balancing problem. An illustrative example shows the effectiveness of the proposed methodology. [ABSTRACT FROM AUTHOR]

Using the convex semidefinite programming method and superoperator formalism we obtain the finite quantum tomography of some mixed quantum states such as: truncated coherent states tomography, phase tomography and coherent spin state tomography, qudit tomography, N-qubit tomography, where that obtained results are in agreement with those of References (Buzek et al., Chaos, Solitons and Fractals 10 (1999) 981; Schack and Caves, Separable states of N quantum bits. In: Proceedings of the X. International Symposium on Theoretical Electrical Engineering, 73. W. Mathis and T. Schindler, eds. Otto-von-Guericke University of Magdeburg, Germany (1999); Pegg and Barnett Physical Review A 39 (1989) 1665; Barnett and Pegg Journal of Modern Optics 36 (1989) 7; St. Weigert Acta Physica Slov. 4 (1999) 613). [ABSTRACT FROM AUTHOR]

In many theoretical proposals appeared recently, semidefinite programming was considered as a way to express quantum entanglement. Using semidefinite optimization method, we prove the Lewenstein–Sanpera lemma in a simple elegant manner. Particularly, using this method we obtain Lewenstein–Sanpera decomposition for some examples such as: generic two qubit state in Wootters’s basis, Iso-concurrence state, Bell decomposable state and 2 ⊗ 3 Bell decomposable state. [ABSTRACT FROM AUTHOR]

This review focuses on the synthesis, protection, functionalization, characterization and with some applications of magnetic nanoparticles (MNPs). The review begins with an overview on magnetic property and single domain particles. The synthetic strategies developed for the generation of MNPs, with a focus on particle formation mechanism and recent modifications made on the synthesis of monodisperse samples of relatively large quantities are also discussed. Then, different methodologies for the protection and functionalization of the synthesized MNPs, together with the characterization techniques are explained. Finally, some of the recent industrial, biological, environmental and analyticals application of MINPs are briefly reviewed, and some future trends and perspectives in these research areas will be outlined. [ABSTRACT FROM AUTHOR]