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This paper focuses on modelling, control, realisation and performance analysis of a full-scale demonstrator for a novel railway track switch. For over a century, railway track switches (or points) have been allowing trains to safely change between routes. As they are safety-critical elements of the rail network, when they fail, the signalling system will prevent trains from using that route. This means poor reliability (or lack of availability) leads to significant delays and costs; hence there is huge interest from researchers and engineers in improving the overall reliability of track switches. This paper presents new results, which represent a meaningful first step toward a revolution in the way track switches are actuated. A "REPOINT-Light" railway track switch demonstrator is introduced which uses a new concept of locking to allow redundant actuation with three actuator bearers operating under closed-loop feedback control. The new concept, its control system and its mechanical viability are tested in experiments at the Great Central Railway in the UK. To support the design of the actuators and the control system, a dynamic simulation model is developed by co-simulation involving Simulink and Simpack. The experimental results presented are used to validate the models and the paper discusses how the models themselves are used as the vehicle for the design of feedback controllers. Virtual testing of the controllers in simulation is a vital step prior to the implementation and deployment of the controllers in the demonstrator switch. The major contribution of this work is demonstrating, for the first time at full scale on a real-world track switch, that it is possible to use one-out-of-three actuator redundancy to provide fault-tolerant operation of railway track switch. [ABSTRACT FROM AUTHOR]

Abstract: Indirect combustion noise is believed to be a key component of turbofan engine core noise, but existing experimental data have not been able to definitively determine its importance. Instead, actuator disk theory (ADT) as developed by Cumpsty and Marble [The interaction of entropy fluctuations with turbine blade rows; a mechanism of turbojet noise, Proceedings of the Royal Society of London A 357 (1977) 323–344] is commonly used to estimate its contribution based on combustor exit conditions and changes in the mean flow across blade rows. The theory, which assumes planar propagation of acoustic, entropic, and vortical waves in the long wavelength limit, is assessed by comparing its predictions to those from two-dimensional compressible Euler calculations of idealized entropy disturbances interacting with a 1980s era NASA turbine stator. Both low-frequency planar waves of constant frequency and higher-frequency, localized entropy disturbances are considered, with the former being within ADT''s range of applicability and the latter outside of it. It is found that ADT performs well for the cut-on acoustic modes generated by the entropy-blade interaction but its accuracy suffers for the cut-off acoustic modes, which could impact indirect combustion noise predictions for turbines with closely spaced blade rows. [Copyright &y& Elsevier]

During the last decade, optical tweezers have been transformed by the combined availability of spatial light modulators and the speed of low-cost computing to drive them. Holographic optical tweezers can trap and move many objects simultaneously and their compatibility with other optical techniques, particularly microscopy, means that they are highly appropriate to lab-on-chip systems to enable optical manipulation, actuation and sensing. [ABSTRACT FROM AUTHOR]

As part of the All-Electric Ship concept the Ministry of Defence (MoD) Defence Procurement Agency Future Business Group's Marine Engineering Development Programme (MEDP) has been investigating the Electrical Actuation of Hydrodynamic Control Surfaces (ELAHCS) Programme for the Royal Navy. The project is presently examining the replacement of traditional hydraulic actuation systems for fixed-fin ship stabilizers, steering gear, and hydroplane actuation with novel electric actuation methods. As part of this programme the project has developed a technical demonstrator – a fixed-fin stabilizer actuator – which was fitted to both stabilizers on an operational Type 23 Frigate as part of a System Demonstrator Programme (SDP). This demonstrator is providing system performance and environmental data and contributing to the wider understanding of hydrodynamic control surface requirements. It is also illustrating the potential benefits of this technology which are reduced lifecycle costs, simpler installation and maintenance, improved survivability, cleaner systems, elimination of high-energy fluidic systems, and hence the associated support and training and hazards. This paper describes the development of the ELAHCS Programme, the progress of the SDP to date, and additional future exploitation of this technology for ship and submarine applications. [ABSTRACT FROM AUTHOR]

The article offers information about the Rotork intelligent valve actuators which took center stage at the latest official opening of the new skills and maintenance training centre at the British Energy Heysham power station. The new facility provides individual workshop and classroom education for maintenance and engineering staff at Heysham. It also facilitates important abilities such as valve commissioning, maintenance and faultfinding which must be observed. The valve actuators are significant in power station control systems.

The article informs about Scottish Power PLC's purchase of electric actuators worth £300,000 from ABB Ltd. for its Longannet power plant. The Longannet power plant is the largest power plant of Europe and second largest coal-fired power station in Great Britain. The plant produces 600MW of electricity, serving the need of two million people. Eight pulverized mills are used to fulfill the coal demand of Longannet's four generating units. Dampers are installed to control the combustion produced from mills. Around 56 part-turn actuators are designed to control the mill dampers which are sufficient for three to four production units. Other actuators from ABB Ltd. regulate valves to control the flow of water entering into the boiler.