A robust predictive model for base shear of steel frame structures using a hybrid genetic programming and simulated annealing method

This study presents a new empirical model to estimate the base shear of plane steel structures subjected to earthquake load using a hybrid method integrating genetic programming (GP) and simulated annealing (SA), called GP/SA. The base shear of steel frames was formulated in terms of the number of bays, number of storey, soil type, and situation of braced or unbraced. A classical GP model was developed to benchmark the GP/SA model. The comprehensive database used for the development of the correlations was obtained from finite element analysis. A parametric analysis was carried out to evaluate the sensitivity of the base shear to the variation of the influencing parameters. The GP/SA and classical GP correlations provide a better prediction performance than the widely used UBC code and a neural network-based model found in the literature. The developed correlations may be used as quick checks on solutions developed by deterministic analyses.     

Adiabatic nanofocusing scattering-type optical nanoscopy of individual gold nanoparticles

We explore imaging of local electromagnetic fields in the vicinity of metallic nanoparticles using a grating-coupled scattering-type near-field scanning optical microscope. In this microscope, propagating surface plasmon polariton wavepackets are launched onto smooth gold tapers where they are adiabatically focused toward the nanometer-sized taper apex. We report two-dimensional raster-scanned optical images showing pronounced near-field contrast and demonstrating sub-30 nm resolution imaging of localized surface plasmon polariton fields of spherical and elliptical nanoparticles. By comparison to three-dimensional finite-difference time domain simulations, we conclude that virtually background-free near-field imaging is achieved. The microscope combines deep subwavelength resolution, high local field intensities and a straightforward imaging contrast, making it interesting for a variety of applications in linear and nonlinear nanospectroscopy.     

Oxidative desulfurization of 4,6-dimethyldibenzothiophene in a two impinging streams spray reactor

Oxidative desulfurization of 4,6-dimethyldibenzothiophene was performed in a two impinging streams spray reactor (TIS-SR) using H₂O₂ and phosphotungstic acid as oxidant and catalyst, respectively. The reaction was optimized using response surface methodology. The reaction constant of a pseudo first order rate based on the dynamic data obtained for the optimal operation conditions was calculated to be 9.45 × 10^?4 s^?1. It is about one order of magnitude larger than the one calculated for a conventional ideal stirred batch reactor at the same reaction conditions (1.03 × 10^?4 s^?1). Accordingly, ODS reaction rate may be substantially enhanced using TIS-SR.     

DLS: A dynamic local stitching mechanism to rectify transmitting path fragments in wireless sensor networks

In this paper, a pair of novel rectification algorithms (greedy negative pressure push algorithm and dynamic local stitching algorithm) is proposed to cooperatively repair broken transmitting paths in Wireless Sensor Networks. Our approach is to overcome the poor data validity in WSNs, specifically for harsh application environments – such as unattended sensor nodes or frail wireless transmitting channels – where fault tolerant becomes a vital aspect. Using adjacency information, Greedy negative pressure push algorithm can efficiently grow the transmitting path to achieve the minimum energy consumption for relays model. Here, we measured packet travel time and the expectation of relay distance to set this model's key parameters to achieve the lowest possible end-to-end transmitting delay. Dynamic local stitching algorithm has a major difference with other existing routing algorithms in rectifying broken paths; despite others that reroute whole paths, our algorithms only stitch broken fragments of the original path spending minimum amount of energy as well as recovery time. Based on mathematical computing and simulation, our novel rectification algorithm could effectively (1) reduce the total number of routing overheads, (2) improve net throughput, and (3) increase system fault tolerant much better than four already designed routing algorithms. Results were also very promising to motivate other algorithms in this field.     

NiFe2O4@SiO2–PPA Nanoparticle: A Green Nanocatalyst for the Synthesis of β-Acetamido Ketones

ABSTRACT

In this work, silica coated magnetic nanoparticles of modified polyphosphoric acid (NiFe₂O₄@SiO₂–PPA deigned as NFS–PPA) represent as a reusable and green catalyst for one-pot four-component synthesis of β-acetamido ketones at room temperature under solvent-free conditions. This catalyst was synthesized and characterized by X-ray diffractions, transmission electron microscopy, scanning electron microscopy and vibrating sample magnetometry. The magnetic catalyst can be easily removed by a simple magnet and reused up to five times without any loss of its high catalytic activity. In addition to facility, this protocol enhances product purity and promises economic and also environmental profits.