Toque C.,Tech Hampshire |
Milodowski A.E.,British Geological Survey |
Baker A.C.,UK Defence Science and Technology Laboratory
Journal of Environmental Radioactivity | Year: 2014
Depleted Uranium alloyed with titanium is used in armour penetrating munitions that have been fired in a number of conflict zones and testing ranges including the UK ranges at Kirkcudbright and Eskmeals. The study presented here evaluates the corrosion of DU alloy cylinders in soil on these two UK ranges and in the adjacent marine environment of the Solway Firth.The estimated mean initial corrosion rates and times for complete corrosion range from 0.13 to 1.9gcm-2y-1 and 2.5-48 years respectively depending on the particular physical and geochemical environment.The marine environment at the experimental site was very turbulent. This may have caused the scouring of corrosion products and given rise to a different geochemical environment from that which could be easily duplicated in laboratory experiments.The rate of mass loss was found to vary through time in one soil environment and this is hypothesised to be due to pitting increasing the surface area, followed by a build up of corrosion products inhibiting further corrosion. This indicates that early time measurements of mass loss or corrosion rate may be poor indicators of late time corrosion behaviour, potentially giving rise to incorrect estimates of time to complete corrosion.The DU alloy placed in apparently the same geochemical environment, for the same period of time, can experience very different amounts of corrosion and mass loss, indicating that even small variations in the corrosion environment can have a significant effect. These effects are more significant than other experimental errors and variations in initial surface area. © 2013.
Chaplin R.A.,Tech Hampshire
31st AIAA Applied Aerodynamics Conference | Year: 2013
Lateral reaction jets can be used to control modern weapons and offer faster actuation times than conventional control surfaces. The main disadvantage is the complex interaction flowfield which results between the jet and the crossflow. The aim of this paper is to assess the ability of Computational Fluid Dynamics (CFD) to predict this flowfield for a supersonic lateral jet injected into a transonic crossflow on a flat plate. The predicted jet interaction flowfield was highly sensitive to the turbulence model used, with the Spalart-Allmaras model performing best. The key interaction flow features were well predicted by the CFD across a range of jet pressure ratios and Mach numbers although there were some discrepancies in the predicted jet plume and vortex locations. The predicted results showed that the jet interaction flowfield was relatively insensitive to freestream Mach number.
Cleminson J.R.,Tech Hampshire
AIAA Aerodynamic Decelerator Systems (ADS) Conference 2013 | Year: 2013
The problem of path planning for the precision landing of autonomously-guided parafoil-payload systems is considered for the class of systems that are unpowered and controlled only through the application of lateral steering. The problem is challenging because there is little control over forward speed or descent rate, yet there is strong dependence on wind conditions, which can significantly influence the shape of the trajectory or indeed the feasibility of the problem; there is only one chance at a precision landing. A formulation based on discrete, deterministic Dynamic Programming is proposed to analyse the problem and provide a means of generating feasible trajectories. The formulation accounts for the kinematics of the parafoil in a wind field in a simplified manner to render solutions more tractable and computationally efficient, albeit at the expense of some fidelity. © British Crown Copyright 2013/DSTL.
Orfanoudakis G.I.,University of Southampton |
Yuratich M.A.,Tech Hampshire |
Sharkh S.M.,University of Southampton
IEEE Transactions on Power Electronics | Year: 2013
Nearest vector (NV) modulation strategies for the neutral-point-clamped converter are known to generate low-frequency neutral point (NP) voltage oscillations. Non-NV strategies can eliminate these oscillations, but at the expense of higher switching losses and output voltage harmonic distortion. This letter proposes a simple way of creating hybrid strategies, as combinations of NV and non-NV strategies, which are also able to eliminate NP voltage oscillations. The approach minimizes the participation of non-NV strategies and hence their drawbacks, while it can be applied to any type of load (nonlinear and/or unbalanced). Simulations in MATLAB-Simulink are used to illustrate its operation. © 1986-2012 IEEE.
Rowe S.,Tech Hampshire |
Francois J.-M.,DEKRA Insight Process Safety Chilworth SAS
Journal of Loss Prevention in the Process Industries | Year: 2016
Excellence in process safety performance requires an integrated approach to addressing programs, culture and competency. One important aspect of competency is having the right information available, and accessible, to support and underpin the overarching safety management system. This includes both asset information such as P&ID's, equipment specifications, instrumentation, piping and physical equipment inventory, safety systems, safety instrumented functions, etc and process information such as batch manufacturing records, quality/IPC procedures, raw material information, material safety data, process safety data, etc. Whilst the requirements for asset information and most process information is reasonably prescriptive - and hence can be reliably audited and assured - the specification of required process safety data is far from prescriptive. This often leads to ineffective or inefficient systems and can completely undermine otherwise excellent process safety management systems. © 2016 Elsevier Ltd.