Wake structure and kinematics in the vortex ring state

High-resolution computational simulations of the vortical wake of a rotor operating both near to and within the vortex ring state have been conducted using Brown's vorticity transport model. The nonlinear vortex kinematics of the wake is exposed using three-dimensional visualizations of the simulated flow field. To reveal the vortex dynamics that underpin the highly unsteady flow within the vortex ring state, a rotor with just one blade was modeled. This blade was decoupled aerodynamically from the surrounding velocity field so that it acted merely as a source of trailed vorticity. The investigation identified a significant change in the dominant dynamics of the wake as it swapped fromthe tubular form that is characteristic of hover or very lowspeed descent into the toroidal geometry of the vortex ring state. Initial vortex 'pairing' leads to rotation of vortex filaments away from their original attitude. This phenomenon plays an important role in regulating the downwash that the rotor can produce and thus in precipitating the onset of the vortex ring state. The considerable and persistent coherence of the vortical structure of the wake when in the vortex ring state is revealed, despite these disturbances, as are themechanisms that lead to both small-scale and large-scale wake breakdown events. Simulations show the balance between the vortex pairing and short-wave instability modes to be different in the vortex ring state at high descent speed, where the wake lies above the rotor, compared to in the vortex ring state at low descent speed when the wake lies predominantly below the rotor. This yields subtle differences to the kinematics and structure of the wake in the two cases

A provisional survey of the interaction between net photosynthetic rate, respiratory rate, and thallus water content in some New Zealand cryptogams

The effect of water content on photosynthetic and respiratory rates in eight lichen species and one bryophyte species were studied using an injection infrared gas analyser technique. All species snowed a strong relationship between net assimilation rate (NAR), respiration rate, and water content similar to relationships reported in published studies overseas. Species from moist habitats showed negative NAR at low water contents. Species from high-light areas showed a depression in NAR at high water contents which could be alleviated by higher light intensities. The experiments confirmed the suitability of New Zealand species for these studies

Employers skill survey : case study : health and social care

"This report examines the relationship between service delivery strategies and processes, and the deployment of skills, recruitment problems and skill gaps within selected sub-sectors of health and social care. The sub-sectors within health are physiotherapy and radiography. Within social care the focus is on care of the elderly (both residential and domiciliary care). Although subject to similar drivers and associated pressures, the two sub-sectors of health and social care display markedly different characteristics, particularly in terms of service delivery strategies, qualification frameworks and utilisation of skills. In simple terms, the health and social care subsectors considered within this report may be thought of as being situated at opposite poles of the ‘skills spectrum’: with radiography and physiotherapy characterised by high level skills, while care of the elderly is traditionally associated with low level skills. Hence, the two sub-sectors are discussed separately throughout this report. The greater complexity and range of skills required in the two health sub-sectors is reflected in the comparative length of the two sections of the report" - page 9

Total Synthesis and Structural Revision of the Alkaloid Incargranine B

Seeing double: Consideration of the biosynthetic origins of incargranineB, which was originally assigned an unprecedented indolo[1.7]naphthyridine structure, led to the proposal of a dipyrroloquinoline framework as a more biosynthetically feasible struct

Consuming Linked Data within a Large Educational Organization

Large universities tend to spread their services across several departments to serve their substantial student base. It is very common for this to result in developing different systems, which end up in creating many disconnected data silos within the organization. Data isolation is one of the main bottlenecks that prevent unlocking the full potential behind exploiting such data, to provide a better experience at the level of application deployment and data analysis. The Open University is in the process of connecting their data silos by relying on the Linked Data principles within the LUCERO project. We discuss in this paper three use-cases through which we consume Linked Data produced at the Open University: (1) a student services use-case showing how we exploit data connections to deliver learning material related to courses through the university's main course information website; (2) a mobile course application that enables students to easily explore courses by subject, qualification or research topic; and (3) a Leanback TV service that provides students the ability to watch, with a degree of control, a set of podcasts grouped in different channels. Through these use cases, we highlight in this paper the advantages and effects of consuming Linked Data within an organization

A sub-regional management framework for South Pacific longline fisheries

The principal objective of this study was to determine if additional net benefits can be derived from the sub-regional longline fishery by the introduction of a new management agreement that would centre on the provision of licensing arrangements that would allow access by eligible longline vessels to multiple Exclusive Economic Zones, i.e. Multi-zone Access. [90pp.

Simulation of wind turbine wake interaction using the vorticity transport model

The aerodynamic interactions that can occur within a wind farm can result in the constituent turbines generating a lower power output than would be possible if each of the turbines were operated in isolation. Tightening of the constraints on the siting of wind farms is likely to increase the scale of the problem in the future. The aerodynamic performance of turbine rotors and the mechanisms that couple the fluid dynamics of multiple rotors can be most readily understood by simplifying the problem and considering the interaction between only two rotors. The aerodynamic interaction between two rotors in both co-axial and offset configurations has been simulated using the Vorticity Transport Model. The aerodynamic interaction is a function of the tip speed ratio, and both the streamwise and crosswind separation between the rotors. The simulations show that the momentum deficit at a turbine operating within the wake developed by the rotor of a second turbine is governed by the development of instabilities within the wake of the upwind rotor, and the ensuing structure of the wake as it impinges on the downwind rotor. If the wind farm configuration or wind conditions are such that a turbine rotor is subject to partial impingement by the wake produced by an upstream turbine, then significant unsteadiness in the aerodynamic loading on the rotor blades of the downwind turbine can result, and this unsteadiness can have considerable implications for the fatigue life of the blade structure and rotor hub

An evaluation of the Wii Nunchuk as an alternative assistive device for people with intellectual and physical disabilities using switch controlled software

Many people with intellectual disabilities also have physical difficulties which prevent them from using standard computer control devices. Custom made alternative devices for those with special needs can be expensive and the low unit turnover makes the prospect unattractive to potential manufacturers. One solution is to explore the potential of devices used in contemporary gaming technology, such as the Nintendo Wii. The Wii Nunchuk has the potential to replace joystick functions with the advantages of not being surface bound and easier for some individuals to grasp. This study evaluated the feasibility of using the Nunchuk by comparing its performance as a switch with the participant's usual switch. Twenty three volunteers aged between 17 and 21 with intellectual and physical disabilities completed a Single Switch Performance Test using the new device and their familiar device. For most functions of the switch, there was no significant difference between the participants' performance using the Nunchuck and their familiar device. Additional analysis found that some participants' performance did improve whilst using the Nunchuck, but this was not significantly related to physical or cognitive ability. Those whose performance was better with the Nunchuk were more likely to hold it in the conventional way than were those who had better performance with their familiar device. This merits it being offered as a possible alternative to currently available switches for those with physical difficulties affecting their grip