Multiquadrics collocation method for transient eddy current problems

This paper presents the multiquadrics collocation method (MQCM) for transient eddy current problems. Both the implicit scheme and Crank-Nicolson time matching scheme are used here for time discretization. An example on analyzing transient eddy current of a square metal column is illustrated to prove the accuracy and affectivity of the proposed method. © 2006, IEEE. All rights reserved

Failure analysis of a steel motorcycle kickstand

Copyright @ 2009 Springer US.A fractured steel motorcycle kickstand was metallurgically investigated using a range of failure analysis tools [visual examination, energy dispersive X-ray (EDX) analysis, electron microprobe analysis (EPMA), scanning electron microscopy (SEM), fractography, optical microscopy, hardness testing and non-destructive testing (NDT)]. The steel kickstand’s composition, its microstructure, electron fractographs, and mechanical test results have been critically interpreted. Some evidence of wear damage, in the failed kickstand, was observed. The microstructural and fractographic analyses showed pre-existing micro-cracks which were believed to have grown to result in ductile failure followed by acceleration of corrosion. Recommendations have been made to avoid the failure of the motorcycle kickstand

Emerging Methods for Color Image and Video Quality Enhancement

n/

An improved multiquadric collocation method for 3-D electromagnetic problems

The multiquadric radial basis function method (MQ RBF or, simply, MQ) developed recently is a truly meshless collocation method with global basis functions. It was introduced for solving many 1- and 2-D partial differential equations (PDEs), including linear and nonlinear problems. However, few works are found for electromagnetic PDEs, especially for 3-D problems. This paper presents an improved MQ collocation method for 3-D electromagnetic problems. Numerical results show a considerable improvement in accuracy over the traditional MQ collocation method, although both methods are direct collocation method with exponential convergence. © 2007 IEEE

Permeability is the critical factor governing the life cycle environmental performance of drinking water treatment using living filtration membranes.

Living Filtration Membranes (LFMs) are a water filtration technology that was recently developed in the lab (Technology Readiness Level 4). LFMs have shown filtration performance comparable with that of ultrafiltration, far better fouling resistance than conventional polymer membranes, and good healing capabilities. These properties give LFMs promise to address two significant issues in conventional membrane filtration: fouling and membrane damage. To integrate environmental considerations into future technology development (i.e., Ecodesign), this study assesses the life cycle environmental performance of drinking water treatment using LFMs under likely design and operation conditions. It also quantitatively ranks the engineering design and operation factors governing the further optimization of LFM environmental performance using a global sensitivity analysis. The results suggest that LFMs' superior fouling resistance will reduce the life cycle environmental impacts of ultrafiltration by 25% compared to those of a conventional polymer membrane in most impact categories (e.g., acidification, global warming potential, and carcinogenics). The only exception is the eutrophication impact, where the need for growth medium and membrane regeneration offsets the benefits of LFMs' fouling resistance. Permeability is the most important factor that should be prioritized in future R&D to further improve the life cycle environmental performance of LFMs. A 1% improvement in the permeability will lead to a ∼0.7% improvement in LFMs' environmental performance in all the impact categories, whereas the same change in the other parameters investigated (e.g., LFM lifespan and regeneration frequency) typically only leads to a <0.2% improvement

Multiscale combined radial basis function collocation method for eddy currents analysis in high-speed moving conductors

A novel multiscale combined radial basis function (RBF) collocation method, as a truly meshless method, is presented to overcome the shortage of general RBF collocation method and is applied to analyze eddy currents in high-speed moving conductors in this paper. A typical example is set here to illustrate the accuracy and affectivity of the proposed method, including a comparison with general RBF collocation method and finite element method (FEM). © 2009 IEEE

Bridge-specific fragility analysis: when is it really necessary?

In seismic assessment of bridges the research focus has recently shifted on the derivation of bridge-specific fragility curves that account for the effect of different geometry, structural system, component and soil properties, on the seismic behaviour. In this context, a new, component-based methodology for the derivation of bridge-specific fragility curves has been recently proposed by the authors, with a view to overcoming the inherent difficulties in assessing all bridges of a road network and the drawbacks of existing methodologies, which use the same group of fragility curves for bridges within the same typological class. The main objective of this paper is to critically assess the necessity of bridge-specific fragility analysis, starting from the effect of structure-specific parameters on component capacity (limit state thresholds), seismic demand, and fragility curves. The aforementioned methodology is used to derive fragility curves for all bridges within an actual road network, with a view to investigating the consistency of adopting generic fragility curves for bridges that fall within the same class and quantifying the degree of over- or under-estimation of the probability of damage when generic bridge classes are considered. Moreover, fragility curves for all representative bridges of the analysed concrete bridge classes are presented to illustrate the differentiation in bridge fragility for varying structural systems, bridge geometry, total bridge length and maximum pier height. Based on the above, the relevance of bridge-specific fragility analysis is assessed, and pertinent conclusions are drawn

A novel superposition RBF collocation method to solve moving conductor eddy current problems

This paper presents a novel radial basis function (RBF) collocation method to solve the moving conductor eddy current problem. The magnetic field is considered an addition of two fields generated respectively by the excitation current and the eddy current according to the source superposition principle. The corresponding governing equations are decoupled and solved with the RBF. Moving coordinate systems in which the separate fields are computed are also constructed to avoid the model reconfiguration caused by the motion. Electromagnetic field equations are analyzed with kinetic equations and circuit equations together to simulate the motion process. A practical engineering problem is computed to verify the method. © 2009 IEEE