Implementation of a low-mach number modification for high-order finite-volume schemes for arbitrary hybrid unstructured meshes

An implementation of a novel low-mach number treatment for high-order finite-volume schemes using arbitrary hybrid unstructured meshes is presented in this paper. Low-Mach order modifications for Godunov type finite-volume schemes have been implemented successfully for structured and unstructured meshes, however the methods break down for hybrid mesh topologies containing multiple element types. The modification is applied to the UCNS3D finite-volume framework for compressible flow configurations, which have been shown as very capable of handling any type of grid topology. The numerical methods under consideration are the Monotonic Upstream-Centered Scheme for Conservation Laws (MUSCL) and the Weighted Essentially Non-Oscillatory (WENO) schemes for two-dimensional mixed-element type unstructured meshes. In the present study the HLLC Approximate Riemann Solver is used with an explicit TVD Runge-Kutta 3rd-order method due to its excellent scalability. These schemes (up to 5th-order) are applied to well established two-dimensional and three-dimensional test cases. The challenges that occur when applying these methods to low-mach flow configurations is thoroughly analysed and possible improvements and further test cases are suggested

Using Web 2.0-Based Groupware to Facilitate Collaborative Design in Engineering Education Scheme Projects

Employee collaboration is vital for manufacturing organisations wishing to be successful in an ever-changing global market place; it is commonly referred to as the joining of people and interests to meet a common goal via visual or oral interaction, information and knowledge sharing and the coordination of tasks; product development teams operating within the aerospace and defence industry rely extensively on this. To this end, the purpose of this paper is to present the results of a validation study carried out during an Engineering Education Scheme (EES) project initiated by a leading aerospace and defence manufacturing organisation, to confirm the benefits of using bespoke Web 2.0-based groupware to improve employee collaboration between dispersed teams. The results of a cross-sectional survey concluded that employees in the collaborating organisations would welcome greater usage of Web 2.0-based technologies. The study confirmed that groupware offers the potential to deliver a more effective collaborative environment with additional communication channels on offer to end users

A new paradigm for virtual knowledge sharing in product development based on emergent social software platforms

The UK Government considers its Aerospace Industry a remarkable success story, enjoying a global market share of 17% in 2015. The capture, management and sharing of employee knowledge is seen as vital if the industry is to remain highly innovative and retain its pre-eminent position internationally. Aerospace manufacturers, such as BAE Systems, often have to re-engineer business processes routinely to ensure their survival. Knowledge sharing in the industry is seen as challenging due to the dispersed nature of its operations and multi-tier supply chains. This article, through a 5-year participant-observation study at the World’s second largest aerospace and defence organisation, BAE Systems, proposes a new paradigm for virtual knowledge sharing in dispersed aerospace product development based on emergent social software platforms such as Enterprise 2.0 technologies. The developed framework and methodologies are applied to the bespoke BAE Systems’ engineering lifecycle process to validate its effectiveness with results indicating that Enterprise 2.0 technologies offer a more openly innovative environment in which employees may share and interact with knowledge more effectively and easily across geographical and functional boundaries, compared with conventional engineering information systems

Integrating social knowledge and collaboration tools into dispersed product development

Employee collaboration and knowledge sharing is vital for manufacturing organisations wishing to be successful in an ever-changing global market place; Product Development (PD) teams, in particular, rely heavily on these activities to generate innovative designs and enhancements to existing product ranges. To this end, the purpose of this paper is to present the results of a validation study carried out during an Engineering Education Scheme project to confirm the benefits of using bespoke Web 2.0-based groupware to improve collaboration and knowledge sharing between dispersed PD teams. The results of a cross-sectional survey concluded that employees would welcome greater usage of social computing technologies. The study confirmed that groupware offers the potential to deliver a more effective collaborative and knowledge sharing environment with additional communication channels on offer. Furthermore, a series of recommended guidelines are presented to show how PD teams, operating in globally-dispersed organisations, may use Web 2.0 tools to improve employee collaboration and knowledge sharing

A phononic bandgap shield for high-Q membrane microresonators

A phononic crystal can control the acoustic coupling between a resonator and its support structure. We micromachine a phononic bandgap shield for high Q silicon nitride membranes and study the driven displacement spectra of the membranes and their support structures. We find that inside observed bandgaps the density and amplitude of non-membrane modes are greatly suppressed, and membrane modes are shielded from an external mechanical drive by up to 30 dB.Comment: 5 pages, 4 figure

Observation of ferromagnetism above 900 K in Cr-GaN and Cr-AlN

We report the observation of ferromagnetism at over 900K in Cr-GaN and Cr-AlN thin films. The saturation magnetization moments in our best films of Cr-GaN and Cr-AlN at low temperatures are 0.42 and 0.6 u_B/Cr atom, respectively, indicating that 14% and 20%, of the Cr atoms, respectively, are magnetically active. While Cr-AlN is highly resistive, Cr-GaN exhibits thermally activated conduction that follows the exponential law expected for variable range hopping between localized states. Hall measurements on a Cr-GaN sample indicate a mobility of 0.06 cm^2/V.s, which falls in the range characteristic of hopping conduction, and a free carrier density (1.4E20/cm^3), which is similar in magnitude to the measured magnetically-active Cr concentration (4.9E19/cm^3). A large negative magnetoresistance is attributed to scattering from loose spins associated with non-ferromagnetic impurities. The results indicate that ferromagnetism in Cr-GaN and Cr-AlN can be attributed to the double exchange mechanism as a result of hopping between near-midgap substitutional Cr impurity bands.Comment: 14 pages, 4 figures, submitted to AP

An Investigation into the Potential Use of Social Media Technologies to improve the Product Development Functions within the Aerospace and Defence Industry

Competition in global markets has resulted in increased demands for improvements in manufacturing processes. Enterprises have to re-engineer work practices and have shown that the effective communication of knowledge is fundamental to Product Development (PD). It is vital that cross-functional internal and external collaboration is optimised within PD processes and this should be facilitated through early, frequent and effective communication of information and knowledge. Social Media sites represent a new stage in the evolution of the Internet. Sites such as Facebook and Twitter, offer users the ability to stay connected online with friends and colleagues around the world in real-time; similarly, they offer the ability to locate expertise, knowledge and solutions to problems. The results of an industrial investigation, carried out within a leading aerospace and defence organisation, are commented upon and an interactive groupware solution is introduced, which aims to facilitate collaboration between dispersed product development teams

Improving broadband displacement detection with quantum correlations

Interferometers enable ultrasensitive measurement in a wide array of applications from gravitational wave searches to force microscopes. The role of quantum mechanics in the metrological limits of interferometers has a rich history, and a large number of techniques to surpass conventional limits have been proposed. In a typical measurement configuration, the tradeoff between the probe's shot noise (imprecision) and its quantum backaction results in what is known as the standard quantum limit (SQL). In this work we investigate how quantum correlations accessed by modifying the readout of the interferometer can access physics beyond the SQL and improve displacement sensitivity. Specifically, we use an optical cavity to probe the motion of a silicon nitride membrane off mechanical resonance, as one would do in a broadband displacement or force measurement, and observe sensitivity better than the SQL dictates for our quantum efficiency. Our measurement illustrates the core idea behind a technique known as \textit{variational readout}, in which the optical readout quadrature is changed as a function of frequency to improve broadband displacement detection. And more generally our result is a salient example of how correlations can aid sensing in the presence of backaction.Comment: 17 pages, 5 figure

Evaluating the success of a marine protected area: A systematic review approach.

Marine Protected Areas (MPAs), marine areas in which human activities are restricted, are implemented worldwide to protect the marine environment. However, with a large proportion of these MPAs being no more than paper parks, it is important to be able to evaluate MPA success, determined by improvements to biophysical, socio-economic and governance conditions. In this study a systematic literature review was conducted to determine the most frequently used indicators of MPA success. These were then applied to a case study to demonstrate how success can be evaluated. The fifteen most frequently used indicators included species abundance, level of stakeholder participation and the existence of a decision-making and management body. Using the indicator framework with a traffic light system, we demonstrate how an MPA can be evaluated in terms of how well it performs against the indicators using secondary data from the literature. The framework can be used flexibly. For example, where no MPA data currently exist, the framework can be populated by qualitative data provided by local stakeholder knowledge. This system provides a cost-effective and straightforward method for managers and decision-makers to determine the level of success of any MPA and identify areas of weakness. However, given the variety of motivations for MPA establishment, this success needs to be determined in the context of the original management objectives of the MPA with greater weighting being placed on those objectives where appropriate