35 resultados para Cracking reflection


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Purpose – The purpose of this paper is to report the state-of-the-art of servitization by presenting a clinical review of literature currently available on the topic. The paper aims to define the servitization concept, report on its origin, features and drivers and give examples of its adoption along with future research challenges. Design/methodology/approach – In determining the scope of this study, the focus is on articles that are central and relevant to servitization within a wider manufacturing context. The methodology consists of identifying relevant publication databases, searching these using a wide range of key words and phrases associated with servitization, and then fully reviewing each article in turn. The key findings and their implications for research are all described. Findings – Servitization is the innovation of an organisation's capabilities and processes to shift from selling products to selling integrated products and services that deliver value in use. There are a diverse range of servitization examples in the literature. These tend to emphasize the potential to maintain revenue streams and improve profitability. Practical implications – Servitization does not represent a panacea for manufactures. However, it is a concept of significant potential value, providing routes for companies to move up the value chain and exploit higher value business activities. There is little work to date that can be used to help practitioners. Originality/value – This paper provides a useful review of servitization and a platform on which to base more in-depth research into the broader topic of service-led competitive strategy by drawing on the work from other related research communities.

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Pulsating; tension fatigue tests have been carried out on edge notched specimens of a mild steel. An electrical potential drop technique was used to determine the number of cycles taken to initiate cracks and the rate at which the cracks grew across the specimen. The results could be described by the range of stress intensity factor, which for crack initiation was modified to take account of the notch root radius. Analysis of elastic stress distributions at cracks and notches and models of plasticity at crack tips are used to discuss the results. Limited evidence in the literature indicates that the fracture mechanics approach may provide a general description of crack initiation and growth in notched specimens, and a simple graphical method of calculating fatigue lives is described. The results are used to illustrate the effects of specimen size and geometry on the fatigue life of notched specimens. The relevance of the work to the assessment of the significance of defects in welds is discussed.

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We present a new class of multi-channel Fiber Bragg grating, which provides the characteristics of channelized dispersion but does so with only a single reflection band. Such gratings can provide pure phase control of optical pulses without introducing any deleterious insertion-loss-variation. © 2006 Optical Society of America.

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In this paper we consider the possibility of using intermediate solutions, in which ideal apodisation profile for a dispersion-free, sharp-reflection profile fibre Bragg grating approximated in different degrees. The ideal apodisation profile for a flat dispersion, 50 GHz bandwidth grating was obtained using the layer-peeling algorithm. To verify the modelled results a version of the 5-section grating has been manufactured with excellent agreement between the model and the experimental results. The performance penalty due to multiple reflections from the FBGs in different situations was studied. The results showed that in the approximated gratings some post-compensation must be included to account for the local deviations from zero dispersion. © 2003 IEEE.

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Abstract: This paper offers a critical evaluation of recent Irish industrial policy (IP) experience. It argues that whilst Ireland managed to get some things “right” through its IP, substantial tensions arose through making foreign direct investment (FDI) attraction the centrepiece of policy, without at the same time adopting a more holistic approach in IP which inter alia also placed an emphasis on indigenous firms and entrepreneurship more generally. In particular, greater efforts should have been made much earlier in attempting to embed transnational corporation (TNC)-led activity better into the wider economy, in fostering domestic small firms and entrepreneurship, in promoting clusters, and more generally in evaluating IP more fully – notwithstanding the context which mitigated against such actions. As a result, Ireland as an economy remained vulnerable to strategic decisions made elsewhere by TNC decision makers, with IP effectively contributing to a situation that can be characterised as institutional and strategic failure. Overall, the paper suggests that wholesale emulation of the Irish IP approach is problematic.

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We report on a novel experimental study of a pH-responsive polyelectrolyte brush at the silicon/D2O interface. A poly[2-(diethylamino)ethyl methacrylate] brush was grown on a large silicon crystal which acted as both a substrate for a neutron reflectivity solid/liquid experiment but also as an FTIR-ATR spectroscopy crystal. This arrangement has allowed for both neutron reflectivities and FTIR spectroscopic information to be measured in parallel. The chosen polybase brush shows strong IR bands which can be assigned to the N-D+ stretch, D2O, and a carbonyl group. From such FTIR data, we are able to closely monitor the degree of protonation along the polymer chain as well as revealing information concerning the D2O concentration at the interface. The neutron reflectivity data allows us to determine the physical brush profile normal to the solid/liquid interface along with the corresponding degree of hydration. This combined approach makes it possible to quantify the charge on a polymer brush alongside the morphology adopted by the polymer chains. © 2013 American Chemical Society.

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A compact and low cost fiber sensor based on microfiber with Fresnel reflection is proposed and demonstrated for simultaneous measurement of refractive index (RI) and temperature with high sensitivities. © OSA 2015.

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Although there has been an increased interest in the use of electronic portfolios in higher education over the last five years, relatively little is known about the potential of such tools to support the development of higher order abilities for students, such as reflection, in a structured way that is suitable for assessment. This paper reports the findings from a small-scale research which sets out to compare the outcomes of reflective assignments in two cohorts of participants in a Postgraduate Certificate in Professional Practice in Higher Education in the UK. Participants in the programme were asked to submit reflective accounts using an e-portfolio system as part of their formal assessment. One cohort completed the assessment using some generic guidelines of how to reflect and construct an e-portfolio page without a given template or structure, whereas another cohort was given a specific template with clear assessment criteria to gauge the assembly of their reflections. The authors, who are also tutors in the programme, analysed the submitted reflections following open coding procedures. The analysis found a tendency for the reflection in the first cohort to be merely descriptive without progressing to speculating objectively about answers to relevant analytical questions about the process involved in the ability under scrutiny. In contrast the assignments of cohort two were found to be more insightful in terms of assimilating random bits of materials, thoughts and self-questions into complete reflective accounts. These findings bring some evidence to support and indeed promote a more structured approach to reflective practice, which can be further enhanced through a carefully created e-portfolio template and associated assessment criteria.

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Pavement analysis and design for fatigue cracking involves a number of practical problems like material assessment/screening and performance prediction. A mechanics-aided method can answer these questions with satisfactory accuracy in a convenient way when it is appropriately implemented. This paper presents two techniques to implement the pseudo J-integral based Paris’ law to evaluate and predict fatigue cracking in asphalt mixtures and pavements. The first technique, quasi-elastic simulation, provides a rational and appropriate reference modulus for the pseudo analysis (i.e., viscoelastic to elastic conversion) by making use of the widely used material property: dynamic modulus. The physical significance of the quasi-elastic simulation is clarified. Introduction of this technique facilitates the implementation of the fracture mechanics models as well as continuum damage mechanics models to characterize fatigue cracking in asphalt pavements. The second technique about modeling fracture coefficients of the pseudo J-integral based Paris’ law simplifies the prediction of fatigue cracking without performing fatigue tests. The developed prediction models for the fracture coefficients rely on readily available mixture design properties that directly affect the fatigue performance, including the relaxation modulus, air void content, asphalt binder content, and aggregate gradation. Sufficient data are collected to develop such prediction models and the R2 values are around 0.9. The presented case studies serve as examples to illustrate how the pseudo J-integral based Paris’ law predicts fatigue resistance of asphalt mixtures and assesses fatigue performance of asphalt pavements. Future applications include the estimation of fatigue life of asphalt mixtures/pavements through a distinct criterion that defines fatigue failure by its physical significance.

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The interaction of an Airy pulse with a dielectric layer is investigated theoretically. Approximate analytical expressions for reflected and transmitted waves are derived in the form of Taylor series. These series consist of shifted Airy pulses which are decelerated in time and space and deceleration becomes stronger with a number of a term of series. © 2012 IEEE.