Maximising the interfacial toughness of thin coatings and substrate through optimisation of defined parapmeters

The influence of three parameters, i.e. interfacial roughness λ, coating thickness h and impurity radius r at the coating–substrate interface on interfacial toughness, has been investigated within the framework of two approaches, i.e. thermodynamics and fracture mechanics. The governing equations for both the approaches have been derived independently and then fused to form a governing law for evaluating the interfacial toughness. The analysis in this paper which considers three parameters (λ, h and r) has been divided into three setups. Each setup is used to analyse the effect of one variable parameter on interfacial toughness while keeping the other two parameters constant. Three samples for each setup were prepared considering the requirements of constant and variable parameters for each setup. Simulation techniques founded on the experimental studies have been developed during this research in order to find the optimised values of three parameters. These optimised values act as critical values (boundary point) between coating fail-safe and coating fail conditions. The experiment employed ASTM-B117 test, which is used to analyse the interfacial toughness of samples under each setup. These experiments showed excellent, quantitative agreement with the simulation trends predicted by the theoretical model

Of Neocolonialism, Common Law and Uncodifiable Shari’a: A Reply to Professor An-Na’im

In an earlier article -- Robinson et al., Codifying Shari\u27a: International Norms, Legality & the Freedom to Invent New Forms, http://ssrn.com/abstract=941443 -- the authors report the challenges and opportunities that arose during their commission by the United Nations Development Programme and the Government of the Maldives to produce the first modern comprehensive criminal code based upon Shari\u27a. In this brief essay they respond to published criticisms of that project, which asserted, among other things, that Shari\u27a cannot be codified, that it should not be codified, that the project was a shameful exercise in neocolonialism, that the project was an act of oppression in complicity with an insufficiently democratic government, and that the project was done badly because it got Shari\u27a wrong, because it sometimes did not follow Shari\u27a, or because it was insufficiently sensitive to the methodology and process inherent in Shari\u27a. Available for download at http://ssrn.com/abstract=98285

Visual Tracking and Dynamic Learning on the Grassmann Manifold with Inference from a Bayesian Framework and State Space Models

We propose a novel visual tracking scheme that exploits both the geometrical structure of Grassmann manifold and piecewise geodesics under a Bayesian framework. Two particle filters are alternatingly employed on the manifold. One is used for online updating the appearance subspace on the manifold using sliding-window observations, and the other is for tracking moving objects on the manifold based on the dynamic shape and appearance models. Main contributions of the paper include: (a) proposing an online manifold learning strategy by a particle filter, where a mixture of dynamic models is used for both the changes of manifold bases in the tangent plane and the piecewise geodesics on the manifold. (b) proposing a manifold object tracker by incorporating object shape in the tangent plane and the manifold prediction error of object appearance jointly in a particle filter framework. Experiments performed on videos containing significant object pose changes show very robust tracking results. The proposed scheme also shows better performance as comparing with three existing trackers in terms of tracking drift and the tightness and accuracy of tracked boxes

Adaptive appearance learning for visual object tracking

This paper addresses online learning of reference object distribution in the context of two hybrid tracking schemes that combine the mean shift with local point feature correspondences, and the mean shift under the Bayesian framework, respectively. The reference object distribution is built up by a kernel-weighted color histogram. The main contributions of the proposed schemes includes: (a) an adaptive learning strategy that seeks to update the reference object distribution when the changes are caused by the intrinsic object dynamic without partial occlusion/ intersection; (b) novel dynamic maintenance of object feature points by exploring both foreground and background sets; (c) integration of adaptive appearance and local point features in joint object appearance similarity and local point features correspondences-based tracker to improve [7]; (d) integration of adaptive appearance in joint appearance similarity and particle filter tracker under the Bayesian framework to improve [10]. Experimental results on a range of videos captured by a dynamic/stationary camera demonstrate the effectiveness of the proposed schemes in terms of robustness to partial occlusions, tracking drifts and tightness and accuracy of tracked bounding box. Comparisons are also made with the two hybrid trackers together with 3 existing trackers

A theoretical and experimental study of HFE-7000 in a small scale solar organic Rankine cycle as a thermofluid

The use of thermofluids with boiling temperatures lower than the water, allows the operation of low and medium temperature solar thermal systems on an Organic Rankine Cycle (ORC) to generate both mechanical and heat energy. At the same time, the selection of appropriate thermofluid is an important process and has a significant effect both on the system performance and the environment. Conventional thermofluids such as Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs) have high ozone depletion (ODP) and high global warming (GWP) potential. It is therefore important to investigate novel and environmentally friendly thermofluids to address environmental impacts as global warming and ozone layer depletion. Hydrofluoroethers (HFEs) have zero ODP and relatively low GWP and therefore can be used as a replacement for CFCs and HCFCs. In this study, a small scale solar ORC is designed and commissioned to use HFE 7000 as a thermofluids. The system has a flat plate collector and a vane expander as the heat source and prime mover of the cycle respectively. The system performance is determined through energy analysis. Then, a mathematical model of the cycle is developed and the effect of various operating conditions on the components, as well as the whole cycle is examined through performing simulation analyses. Both the experimental and theoretical research indicates that HFE 7000 offers a viable alternative to be used efficiently in small scale solar ORCs to generate mechanical and heat energy

A Predictive Model for Life Assessment of Automotive Exhaust Mufflers Subject to Internal Corrosion Failure due to Exhaust Gases Condensation

A study has been presented of pitting corrosion on internal walls of automotive exhaust muffler due to exhaust gases condensation. The problem mainly exists in the rear section of exhaust system close to tail end pipe such as muffler, especially when the temperature of muffler does not go up during short distance run or winter. The water vapor condenses on the muffler's inner wall in the form of water droplets. The dissolution of corrosive gases which are coming from internal combustion of engine as well as condensation of low-pH acidic vapors in the water droplet can cause severe pitting corrosion on standard exhaust steel. In this work, an experiment is reported for internal corrosion, by using mufflers as test bed subjected to different environmental conditions. Based on observations, a mechanistic model has been developed which involves three main techniques (i) the dropwise condensation technique predicts the condensation rate and is based on heat and mass transfer theory (ii) the species breakdown in the droplet is established through the main thermodynamic and chemical equilibrium (iii) the pitting corrosion involving pit depth is predicted using electrochemical kinetic reactions, species transport and chemical reactions occurring inside the droplet. Lastly, the accuracy of model has been validated by comparison between experimental and predicted results showing a good agreement

An Optimised Approach of Protecting and Sustaining Large Vehicle System

This article is a synopsis of our research and highlights the outcomes and its impact. It was conducted for the development of a sustainable approach to protect and sustain large vehicles in sheltered environment for their enhanced longevity. In this research various modes of failures linked directly or indirectly to the structural ageing of large vehicles were identified, measured, and analysed. Based upon the research conducted; A frame-work to retard structural failures and in-situ condition monitoring has been proposed with an objective to prolong the structural longevity cost effectively

Development of Nanocomposite Coatings

Special Issue in the Development of Nanocomposite Coatings in nanomaterials was setup with the aim to provide an opportunity to showcase the latest developments within the theme of this special issue. It therefore welcomed research articles and reviews papers, by invitation only, within the context of nanocom-posite coatings for possible publications. There are wide ranging major applications of nanocomposite coat-ings for example corrosion, tribology, machine elements, components, complex interacting systems, and flu-id flow especially within the context of cavitation. We have been witnessing increased application needs to address key global and industrial challenges including energy efficiency, reliability, sustainability and dura-bility of systems and machines. These components and systems are often deployed in harsh operating envi-ronments and conditions, for example, very high and subzero temperatures, extreme pressures, very high loading, exposure to corrosive environment, and starved lubrication. To solve these issues, novel and inno-vative approaches are needed. These solutions include optimisation of surfaces and interfaces through surface modifications and coatings. Development and applications of nanocoatings and nanocomposite coatings are relatively new and developments in this area are underway

Modeling the Effect of Residual and Diffusion-Induced Stresses on Corrosion at the Interface of Coating and Substrate

The effect of residual and diffusion induced stresses on corrosion at the interface of coating and substrate has been analysed within a multidisciplinary approach i.e. material science, solid mechanics and electrochemistry. A self-consistent equation for corrosion current density, involving the combined effect of residual stress and diffusion induced stress is developed. The influences of temperature, moduli ratio, thickness ratio, thermal mismatch ratio and residual stress gradient of coating and substrate on the corrosion current density are then discussed. Results indicate that when the thermal expansion of coating is greater than substrate, the decrease in temperature from fabrication temperature accounts for the same direction of both the residual and the diffusion stresses. This behaviour increases the deflection of coating-substrate system and results in the evolution of tensile residual stress in the coating. The tensile stress opens the pre-existing coating micro crack allowing the diffusion of corrosive agents and therefore, accelerating the corrosion damage to the coating-substrate interface. The model is based on experimental observations conducted to understand the behaviour of corrosion at the coating-substrate interface in the presence of tensile or compressive residual stresses. At the end the model has been validated against the experimental results showing a good quantitative agreement between the predicted theoretical and experimental trends