Towards the design of monolithic decoupled XYZ compliant parallel mechanisms for multi-function applications

This paper deals with the monolithic decoupled XYZ compliant parallel mechanisms (CPMs) for multi-function applications, which can be fabricated monolithically without assembly and has the capability of kinetostatic decoupling. At first, the conceptual design of monolithic decoupled XYZ CPMs is presented using identical spatial compliant multi-beam modules based on a decoupled 3-PPPR parallel kinematic mechanism. Three types of applications: motion/positioning stages, force/acceleration sensors and energy harvesting devices are described in principle. The kinetostatic and dynamic modelling is then conducted to capture the displacements of any stage under loads acting at any stage and the natural frequency with the comparisons with FEA results. Finally, performance characteristics analysis for motion stage applications is detailed investigated to show how the change of the geometrical parameter can affect the performance characteristics, which provides initial optimal estimations. Results show that the smaller thickness of beams and larger dimension of cubic stages can improve the performance characteristics excluding natural frequency under allowable conditions. In order to improve the natural frequency characteristic, a stiffness-enhanced monolithic decoupled configuration that is achieved through employing more beams in the spatial modules or reducing the mass of each cubic stage mass can be adopted. In addition, an isotropic variation with different motion range along each axis and same payload in each leg is proposed. The redundant design for monolithic fabrication is introduced in this paper, which can overcome the drawback of monolithic fabrication that the failed compliant beam is difficult to replace, and extend the CPM’s life.

Dark journeys: Jacques Tourneur's Experiment Perilous

An analysis of Jacques Tourneur's 1944 film

Conflicting expectations in transforming government service processes: the story of e-payment for social welfare in Ireland

Despite its clear potential and attractiveness as a solution to a broad range of societal problems, E-Government has not been adopted to levels predicted in early 2000 literature. Whilst case studies of punctual development of E-Government initiatives abound, few countries have progressed to high levels of maturity in the systematic use of ICT in the relationship between government and citizens. At the same time, the current period brings challenges in terms of access to public services and costs of delivering these services which make the large scale use of ICT by governments more attractive than ever, if not even a necessity. This paper presents a detailed case study of a specific E-Government initiative in Ireland in the area of E-payments for G2C, in the social welfare area. Locating the current initiative in its historical context, it analyses the varied motivations and conflicting requirements of the numerous stakeholders and discusses the constraints that bear on the potential scenarios that could be followed at this point in time.

Understanding the work of the city manager

The managerial behaviour approach to understanding managerial work has developed from research over the course of fifty years. The approach represents a marked departure from mainstream (and still prevalent) management approaches that depict management as a set of general composite functions. The managerial behaviour approach is distinctive in its empirical research background, object, focus and methodology. Its objective is to provide the simple answer to the complex question: what do managers do? However, the emphasis in the studies on managerial behaviour represents a limitation in so far as a context for locating and judging that behaviour is largely absent (Hales, 1986). This paper presents the results of initial research into managers operating in a different and largely neglected context - city councils. The research uses Mintzberg’s (1973) concept of behavioural roles as an analytical tool to explain and understand what city managers do. This study assesses whether these roles adequately capture the important features of managerial work in the city council. It is argued that while Mintzberg’s role framework is useful, structured observation alone does not adequately address the complexities of environments and styles of managers or the cognitive processes of managers. However, by integrating this approach with an appreciation of context and cognitive processes and how they can influence or affect managerial behaviour, we develop a more realistic description of what managers actually do and why they do it.