Comparison of 2nd generation LiDAR wind measurement technique with CFD numerical modelling

With the rapid increase in both on and offshore wind turbine deployment there is a requirement for a better understanding of the flow field in which such devices are deployed. Greater understanding of the flow field is necessary for optimisation of turbine control, turbine design, and machine interaction as well as maximise operation and performance. Advanced measurement tools can characterise the flow regime by either acoustic or laser pulses to measure the line of sight velocity of airborne particles. Such technology facilitates the acquisition of detailed and precise measurements of wind speed and direction remote from the device location; some solutions can even provide detail of the flow structure of the wind in the measurement field. In the current study an analysis of the methodology, relevance and potential of a 2nd generation LiDAR is presented along with results of a deployment at an onshore wind farm. The results demonstrate the potential of the LiDAR to capture details of wind farm flow and structures, along with the potential to corroborate numerical techniques with the measured data. Advances in Computational Fluid Dynamics (CFD) approaches coupled with the availability of significant computational resources makes it possible to conduct a valid comparative assessment. This paper presents the details of this comparative assessment and makes a judgement on the accuracy of the approach. The results show that remote sensing devices offer a useful and accurate capability for wind vector analysis and flow visualisation, along with the flexibility to organise bespoke measurement campaigns. The study also presents methodologies by which such devices can be used as validation tools for CFD

The Darkest Shadows: Deep Mid-Infrared Extinction Mapping of a Massive Protocluster

We use deep $8\:\mu m$ Spitzer-IRAC imaging of a massive Infrared Dark Cloud (IRDC) G028.37+00.07 to construct a Mid-Infrared (MIR) extinction map that probes mass surface densities up to $\Sigma\:\sim 1\:\rm{g~cm^{-2}}$ ($A_V\sim200\:$mag), amongst the highest values yet probed by extinction mapping. Merging with a NIR extinction map of the region, creates a high dynamic range map that reveals structures down to $A_V\sim1\:$mag. We utilize the map to: (1) Measure a cloud mass $\sim7\times10^4\:M_\odot$ within a radius of $\sim8\:$pc. $^{13}$CO kinematics indicate that the cloud is gravitationally bound. It thus has the potential to form one of the most massive young star clusters known in the Galaxy. (2) Characterize the structures of 16 massive cores within the IRDC, finding they can be fit by singular polytropic spheres with $\rho\propto{r}^{-k_\rho}$ and $k_\rho=1.3\pm0.3$. They have $\overline{\Sigma}\simeq0.1-0.4\:\rm{g~cm^{-2}}$ --- relatively low values that, along with their measured cold temperatures, suggest magnetic fields, rather than accretion-powered radiative heating, are important for controlling fragmentation of these cores. (3) Determine the $\Sigma$ (equivalently column density or $A_V$) probability distribution function (PDF) for a region that is near complete for $A_V>3\:$mag. The PDF is well fit by a single log-normal with mean $\overline{A}_V\simeq9\:$mag, high compared to other known clouds. It does not exhibit a separate high-end power law tail, which has been claimed to indicate the importance of self-gravity. However, we suggest that the PDF does result from a self-similar, self-gravitating hierarchy of structure being present over a wide range of scales in the cloud.Comment: 6 pages, 3 figures, 1 table, accepted to ApJ

S.117 MHA 1983 re-visited: the liability of the State and the existence of a duty of care

This article seeks to summarise the movement towards an increased likelihood of branches of the state (in this case, either social services or health trusts) being found to owe a duty of care to specific categories of people. The issue was phrased thus in 2005 by Lord Bingham of Cornhill: ‘The question does arise whether the law of tort should evolve, analogically and incrementally, so as to fashion appropriate remedies to contemporary problems or whether it should remain essentially static, making only such changes as are forced upon it, leaving difficult and. in human terms, very important problems to be swept up by the Convention. I prefer evolution’. In adopting that Darwinian approach to the development of the law, it is necessary to look at the recent history of duties of care that may be owed by the State. The starting point is X v Bedfordshire County Council (1995); the end point (so far) is AK v Central and North West London Mental Health NHS Trust and Royal Borough of Kensington and Chelsea4 (2008)

Analysing Java Identifier Names

Identifier names are the principal means of recording and communicating ideas in source code and are a significant source of information for software developers and maintainers, and the tools that support their work. This research aims to increase understanding of identifier name content types - words, abbreviations, etc. - and phrasal structures - noun phrases, verb phrases, etc. - by improving techniques for the analysis of identifier names. The techniques and knowledge acquired can be applied to improve program comprehension tools that support internal code quality, concept location, traceability and model extraction. Previous detailed investigations of identifier names have focused on method names, and the content and structure of Java class and reference (field, parameter, and variable) names are less well understood. I developed improved algorithms to tokenise names, and trained part-of-speech tagger models on identifier names to support the analysis of class and reference names in a corpus of 60 open source Java projects. I confirm that developers structure the majority of names according to identifier naming conventions, and use phrasal structures reported in the literature. I also show that developers use a wider variety of content types and phrasal structures than previously understood. Unusually structured class names are largely project-specific naming conventions, but could indicate design issues. Analysis of phrasal reference names showed that developers most often use the phrasal structures described in the literature and used to support the extraction of information from names, but also choose unexpected phrasal structures, and complex, multi-phrasal, names. Using Nominal - software I created to evaluate adherence to naming conventions - I found developers tend to follow naming conventions, but that adherence to published conventions varies between projects because developers also establish new conventions for the use of typography, content types and phrasal structure to support their work: particularly to distinguish the roles of Java field names

Influencing T Helper Cell Bias in Autoimmunity

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that affects approximately 400,000 people in the United States every year and results in neurological deficits. Inflammatory events associated with MS include activation of auto-reactive T cells and migration of these and other immune cells into the CNS, leading to a coordinated attack upon oligodendrocytes and demyelination. Most current therapies only treat the symptoms of disease, not the cause, which is still in large part unknown. Therefore, the identification of the etiology of this complex disease and the development of new therapies is of great importance. Targeting these T cells by several mechanisms may prove a valuable strategy for addressing the complex nature of MS. Improvement in clinical signs has occurred in experimental autoimmune encephalomyelitis (EAE), the animal model of MS, with the use altered peptide ligands (APLs) as well as calpain inhibitors. APLs produced hypersensitivity reactions in clinical trials at high doses so the hypothesis was formulated that altering these APLs with non-natural amino acids will improve bioavailability. Calpain is a calcium-mediated neutral protease involved in many normal physiological as well as pathological events. We hypothesize that calpain plays a role in several cellular processes involving T cells including migration as well as subtype bias. Three specific aims were designed to test these hypotheses. First, that aza-amino acid incorporation into APLs would increase protease resistance while preserving antigen recognition. Next, that calpain is involved with T cell migration, specifically chemotaxis, as well as, T helper cell bias, by negatively regulating Th2 type cells. Finally, the combination of APL and calpain inhibitor treatment in an EAE model will result in a therapy that is more effective at reducing clinical signs at lower concentrations than either treatment alone. The data obtained from these experiments indicated: (1) aza-amino acids increase APL protease resistance, (2) calpain is involved with T cell chemotaxis, (3) calpain inhibition results in Th2 proliferation and potentiation and (4) combined calpain inhibitor/APL treatment is effective at reducing clinical signs of EAE; thus suggesting, that combined therapy is a viable strategy for developing MS treatments

Assessment of complex wind turbine wake flow using scanning wind lidar measurements and numerical analysis techniques

Utilising scanning lidar devices deployed in active wind farms the results presented detail the evolution of the wind speed profile in the wake of wind turbines operating in both the on and offshore environment. The results of each of the deployments are compared against a variety of wake simulation models. Focussing on the measurement of wake data at hub height, data captured from the nacelle of an offshore wind turbine detailing flow evolution behaviour across a wide range of operational wind speeds and inlet operating conditions is presented. Binned in 2m/s wind speed bins the measurements clearly show a consistent profile across the captured speed range. This profile encompasses an initial flow deficit from inlet measured on the downstream side of the rotor. For undisturbed inflow this is seen to be around 30%, slightly larger for the disturbed inflow and larger still for waked inflow. Moving downstream the measured flow values indicate a flow evolution to a maximum deficit from inlet at two rotor diameters downstream, the differences between the inflow situations are preserved through to this point. This deficit is at a maximum in the 6-8m/s wind speed bins where the Power Coefficient is at its highest. As the wind speeds increase, and the Power Coefficient decreases, the magnitude of the maximum deficit decreases. Beyond this point the flow recovers towards inlet values. None of the profiles are found to recover fully within thirteen rotor diameters of the rotor plane. The wake simulation models employed each identify different areas of strength in comparison to the lidar measurements. The Eddy-Viscosity model with a Turbulence Intensity of 6% shows the closest correlation with the results at the maximum deficit through the recovery and into the far wake. It does not attempt to model the flow behaviour in the near wake region.Utilising scanning lidar devices deployed in active wind farms the results presented detail the evolution of the wind speed profile in the wake of wind turbines operating in both the on and offshore environment. The results of each of the deployments are compared against a variety of wake simulation models. Focussing on the measurement of wake data at hub height, data captured from the nacelle of an offshore wind turbine detailing flow evolution behaviour across a wide range of operational wind speeds and inlet operating conditions is presented. Binned in 2m/s wind speed bins the measurements clearly show a consistent profile across the captured speed range. This profile encompasses an initial flow deficit from inlet measured on the downstream side of the rotor. For undisturbed inflow this is seen to be around 30%, slightly larger for the disturbed inflow and larger still for waked inflow. Moving downstream the measured flow values indicate a flow evolution to a maximum deficit from inlet at two rotor diameters downstream, the differences between the inflow situations are preserved through to this point. This deficit is at a maximum in the 6-8m/s wind speed bins where the Power Coefficient is at its highest. As the wind speeds increase, and the Power Coefficient decreases, the magnitude of the maximum deficit decreases. Beyond this point the flow recovers towards inlet values. None of the profiles are found to recover fully within thirteen rotor diameters of the rotor plane. The wake simulation models employed each identify different areas of strength in comparison to the lidar measurements. The Eddy-Viscosity model with a Turbulence Intensity of 6% shows the closest correlation with the results at the maximum deficit through the recovery and into the far wake. It does not attempt to model the flow behaviour in the near wake region