988 resultados para Internal friction


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EU Social and Labour Rights have developed incrementally, originally through a set of legislative initiatives creating selective employment rights, followed by a non-binding Charter of Social Rights. Only in 2009, social and labour rights became legally binding through the Charter of Fundamental Rights for the European Union (CFREU). By contrast, the EU Internal Market - an area without frontiers where goods, persons, services and capital can circulate freely – has been enshrined in legally enforceable Treaty provisions from 1958. These comprise the economic freedoms guaranteeing said free circulation and a system ensuring that competition is not distorted within the Internal Market (Protocol 27 to the Treaty of Lisbon). Tensions between Internal Market law and social and labour rights have been observed in analyses of EU case law and legislation. This study explores responses by socio-economic and political actors at national and EU levels to such tensions, focusing on collective labour rights, rights to fair working conditions and rights to social security and social assistance (Articles 12, 28, 31, 34 Charter of Fundamental Rights for the European Union). On the basis of the current Treaties and the CFREU, the constitutionally conditioned Internal Market emerges as a way to overcome the perception that social and labour rights limit Internal Market law, or vice versa. On this basis, alternative responses to perceived tensions are proposed, focused on posting of workers, furthering fair employment conditions through public procurement and enabling effective collective bargaining and industrial action in the Internal Market.

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Transport accounts for 22% of greenhouse gas emissions in the United Kingdom and cars are expected tomore than double by 2050. Car manufacturers are continually aiming for a substantially reduced carbonfootprint through improved fuel efficiency and better powertrain performance due to the strict EuropeanUnion emissions standards. However, road tax, not just fuel efficiency, is a key consideration of consumerswhen purchasing a car. While measures have been taken to reduce emissions through stricter standards, infuture, alternative technologies will be used. Electric vehicles, hybrid vehicles and range extended electricvehicles have been identified as some of these future technologies. In this research a virtual test bed of aconventional internal combustion engine and a range extended electric vehicle family saloon car were builtin AVL’s vehicle and powertrain system level simulation tool, CRUISE, to simulate the New EuropeanDrive Cycle and the results were then soft-linked to a techno-economic model to compare the effectivenessof current support mechanisms over the full life cycle of both cars. The key finding indicates that althoughcarbon emissions are substantially reduced, switching is still not financially the best option for either theconsumer or the government in the long run.

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Tanpura string vibrations have been investigated previously using numerical models based on energy conserving schemes derived from a Hamiltonian description in one-dimensional form. Such time-domain models have the property that, for the lossless case, the numerical Hamiltonian (representing total energy of the system) can be proven to be constant from one time step
to the next, irrespective of any of the system parameters; in practice the Hamiltonian can be shown to be conserved within machine precision. Models of this kind can reproduce a jvari effect, which results from the bridge-string interaction. However the one-dimensional formulation has recently been shown to fail to replicate the jvaris strong dependence on the thread placement. As a first step towards simulations which accurately emulate this sensitivity to the thread placement, a twodimensional model is proposed, incorporating coupling of controllable level between the two string polarisations at the string termination opposite from the barrier. In addition, a friction force acting when the string slides across the bridge in horizontal direction is introduced, thus effecting a further damping mechanism. In this preliminary study, the string is terminated at the position of the thread. As in the one-dimensional model, an implicit scheme has to be used to solve the system, employing Newton's method to calculate the updated positions and momentums of each string segment. The two-dimensional model is proven to be energy conserving when the loss parameters are set to zero, irrespective of the coupling constant. Both frequency-dependent and independent losses are then added to the string, so that the model can be compared to analogous instruments. The influence of coupling and the bridge friction are investigated.

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Li-ion batteries have been widely used in the EVs, and the battery thermal management is a key but challenging part of the battery management system. For EV batteries, only the battery surface temperature can be measured in real-time. However, it is the battery internal temperature that directly affects the battery performance, and large temperature difference may exist between surface and internal temperatures, especially in high power demand applications. In this paper, an online battery internal temperature estimation method is proposed based on a novel simplified thermoelectric model. The battery thermal behaviour is first described by a simplified thermal model, and battery electrical behaviour by an electric model. Then, these two models are interrelated to capture the interactions between battery thermal and electrical behaviours, thus offer a comprehensive description of the battery behaviour that is useful for battery management. Finally, based on the developed model, the battery internal temperature is estimated using an extended Kalman filter. The experimental results confirm the efficacy of the proposed method, and it can be used for online internal temperature estimation which is a key indicator for better real-time battery thermal management.

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From March 1999 to August 2000, the authors were involved in simultaneous internal and external evaluations of the social civic and political education (SCaPE) project in Northern Ireland. This project was a major initiative established by the Citizenship Foundation, the Northern Ireland Council for the Curriculum, Examination and Assessment (CCEA), and the School of Education at the University of Ulster at Coleraine. It was a 2-year project in 25 secondary schools established to design, develop, pilot and evaluate a new programme of social, civic and political education for Northern Ireland. It also aimed to serve as a model for future Citizenship curriculum developments throughout Northern Ireland and elsewhere. This paper describes the background to the project, the design and conduct of the two evaluations, and the links between them. It outlines the main conclusions of each evaluation and describes the way SCaPE has since evolved into a mainstream curriculum development project. The final part of the paper analyses the key opportunities, tensions and challenges involved in running such evaluations at a critical time in the history of Northern Ireland – a time when innovation is both necessary and controversial. It argues that, especially in such circumstances, evaluation cannot be conducted from a neutral, objective standpoint, and that it is incumbent on evaluators to recognise the emotional, personal and political commitment they make to the projects in which they are engaged.

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Abstract The material flow in friction stir spot welding of aluminium to both aluminium and steel has been investigated, using pinless tools in a lap joint geometry. The flow behaviour was revealed experimentally using dissimilar Al alloys of similar strength. The effect on the material flow of tool surface features, welding conditions (rotation speed, plunge depth, dwell time), and the surface state of the steel sheet (un-coated or galvanized) have been systematically studied. A novel kinematic flow model is presented, which successfully predicts the observed layering of the dissimilar Al alloys under a range of conditions. The model and the experimental observations provide a consistent interpretation of the stick-slip conditions at the tool-workpiece interface, addressing an elusive and long-standing issue in the modelling of heat generation in friction stir processing.

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The need for companies to consider the environmental impact of their operations and supply chains has been highlighted in the literature. However, few studies appear to consider how companies’ progress from proactive environmental strategies implemented at the internal, operations level to proactive environmental strategies implemented at the supply chain level. This study assesses the implementation process through the lens of the natural resource-based view and dynamic capabilities perspective. First, the link between the internal strategy ‘pollution prevention’ and the supply chain strategy ‘process stewardship’ is assessed. Second, the mediating influence of the internal support processes ‘integration’ and ‘learning’ on the implementation process is considered. Data collected from a sample of 1200 UK-based food manufacturing companies is analysed using multiple regression analysis. The findings suggest that the progression to environmental efforts at the supply chain level begins with internally-based environmental efforts and that the integration of these efforts and experience gained from them are important supporting factors in this progression.