Mobile Model-Based Bridge Lifecycle Management System

Abstract:   This article discusses the requirements for developing a mobile model-based bridge lifecycle management system (MMBLMS). This new system should link all the information about the lifecycle stages of a bridge (e.g., design, construction, inspection, and maintenance) to a 4D model of the bridge incorporating different scales of space and time to record events throughout the lifecycle with suitable levels of details (LoDs). In addition, MMBLMS should support distributed databases and mobile location-based computing by providing user interfaces that can be used on mobile computers, such as tablet PCs. A framework for MMBLMS is described and the basic computational issues for realizing it are discussed including the navigation modes, the picking behavior and the LoDs for representing bridge elements and defects. A prototype system developed in Java language is used to demonstrate the feasibility of the proposed methodology for realizing this system.     

CH4-Selective Mixed-Matrix Membranes Containing Functionalized Silica for Natural Gas Purification

Mixed-matrix membranes were prepared by incorporating functionalized silica nanoparticles (SNPs) into the poly(ether-block-amide). The gas permeation properties of membranes were investigated for the separation of N₂ and CO₂ from CH₄. Results revealed that chemical modification of SNPs and incorporation of the carboxylic groups on its surface had a strong interaction with the polymer matrix and improved the distribution of the nanofiller in the membrane matrix. According to the gas permeation experiments at various SNPs loadings and feed pressures, different trends were observed for the permeability and selectivity. Incorporation of the modified-SNPs nanofiller into the membrane enhanced the CH₄ permeability, as well as the CH₄/N₂ and CO₂/N₂ selectivities.     

Statistical Analysis of Effects of Nanoparticles on Hydrocarbon Pool Fire

The effects of pool diameters, height, fuel type, and presence of nanoparticles on flame temperature are tested. Nanoparticles were added and mixed with the fuel and its effect on flame spread time over the liquid fuel surface is studied. The results showed that pool diameter has the maximum effect on the increase of flame temperature. Nanoparticles reduce the flame temperature from 10 to 20% while flame spread time is increased 15% to 30% for kerosene and 6% to 26% for diesel oil. Experimental measurement of flame temperature distribution in a pool fire is carried out. Statistical analysis of flame temperature, flame spread time was made using Yates and ANOVA methods.     

Investigation of the Effect of Tungsten Substitution on Microstructure and Abrasive Wear Performance of In Situ VC-Reinforced High-Manganese Austenitic Steel Matrix Composite

Particulate VC-reinforced high-manganese austenitic steel matrix composites with different vanadium and tungsten contents were synthesized by conventional alloying and casting route. Microstructural characterizations showed that the composites processed by in situ precipitation of the reinforcements were composed of V₈C₇ particulates distributed in an austenitic matrix. It was observed that addition of tungsten to austenite increases work-hardening rate of subsurface layer during pin-on disk wear test. The maximum abrasive wear resistance was achieved at tungsten content equal to 2 wt pct. However, excessive addition of tungsten promoted the formation of W₃C phase and reduced the abrasive wear resistance because of decrease in distribution homogeneity and volume fraction of the reinforcing VC particles.     

Photocatalytic degradation of reactive black 5 azo dye by zinc sulfide quantum dots prepared by a sonochemical method

Zinc sulfide (ZnS) nanoparticles (NPs) with an average particle size of 2 nm were successfully synthesized under ultrasonic irradiation without any surfactant and high temperature treatment. Prepared NPs were characterized by powder X-ray diffraction, transmission electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared spectroscopy, dynamic light scattering analysis, and UV–vis absorption spectroscopy. The energy band gap of ZnS NPs was measured by UV–vis absorption spectroscopy. The photocatalytic activity of semiconducting sulfide quantum dots for degradation of an azo dye called reactive black 5 (RB5) was investigated. Results showed that the dye can be photocatalytically degraded with high rate by ZnS NPs under UV light irradiation. The kinetics of removal of RB5 in aqueous solutions was studied in a series of experiments which were varied in the amount of ZnS NPs, contact time, pH, dye concentration, and temperature. The experimental data were fitted very well in the pseudo-second order kinetic model. 95% of dye was successfully removed in 10 min using 0.2 g ZnS NPs in a neutral pH. A possible molecular mechanism for photocatalytic degradation of dye by ZnS NPs was also given.     

Determination of Capacity Benefit Margin in Multiarea Power Systems Using Particle Swarm Optimization

Available transfer capability (ATC) is a key index of the remaining capability of a transmission system for future transactions. To calculate the ATC between two areas in an interconnected power system, capacity benefit margin (CBM) is one of the indexes that need to be assessed. CBM ensures security of system operation when the system faces generation deficiency in some areas. In this paper, three new methods are introduced which reflect different objectives for CBM assessment. This provides more flexibility of choices for market participants. In the proposed methods, CBM determination is formulated as an optimization problem and particle swarm optimization (PSO) method is used to solve the problem. The numerical results for modified IEEE reliability test system are presented to demonstrate the effectiveness of the proposed approaches.