Decoupled-DFIG fault ride-through strategy for enhanced stability performance during grid faults

This paper proposes a decoupled fault ride-through strategy for a doubly fed induction generator (DFIG) to enhance network stability during grid disturbances. The decoupled operation proposes that a DFIG operates as an induction generator (IG) with the converter unit acting as a reactive power source during a fault condition. The transition power characteristics of the DFIG have been analyzed to derive the capability of the proposed strategy under various system conditions. The optimal crowbar resistance is obtained to exploit the maximum power capability from the DFIG during decoupled operation. The methods have been established to ensure proper coordination between the IG mode and reactive power compensation from the grid-side converter during decoupled operation. The viability and benefits of the proposed strategy are demonstrated using different test network structures and different wind penetration levels. Control performance has been benchmarked against existing grid code standards and commercial wind generator systems, based on the optimal network support required (i.e., voltage or frequency) by the system operator from a wind farm installed at a particular location.

(Pro)Motion Pictures: Len Lye in the Thirties

This article examines Len Lye’s film-making in the 1930s within a broader visual arts context, seeking to clarify the nature and extent of his involvement in British documentary film culture at this time. In particular, it demonstrates how Lye's method of fusing 'live action', found footage, and animation techniques created the possibility of a radical documentary practice that could reconcile promotional advertising and commercial art with avant-garde abstraction and kinaesthetic experimentation. In particular, the article focusses on Lye's N. or N.W. (1937, 35mm, b&w, 10 mns), arguing that his work from this period should be regarded as central - and not marginal - to any serious reassessment of Britain's “Documentary Movement” of the inter-war era, and its relations to any history of the cinema and visual culture.

Belfast, the emerging city:1850-1914

This explores the rich social, cultural and economic life of Belfast at the point when it was emerging as Ireland's largest city and a key player in the British industrial and commercial landscape. Drawing on the research of established and emerging scholars this provides a series of snapshots of many aspects of the city's devlopment and its people at this pivotal time in its history

In conclusion

This paper will consider ‘the purpose and relevance, process and method, audience and effect of contemporary architectural research in Ireland’ through the lens of one ongoing project, first presented in the paper ‘Vinegar and Chips, Concrete and Linen’ at AIARG Conference in 2012.
The paper however will not reopen the subject of last year’s paper; rather it will deliver the conclusion that the author failed to deliver within the given time. The paper will thus cover ‘a discussion of the contexts of this research i.e. academic, practice-based, craft and commercial’, placing particular emphasis on how these contexts relate to one another and more particularly ‘architectural research’. It will briefly relate the academic discussions that have evolved from the work (digital crafting; feminist forms of practice and technology; design methodology), but will chiefly focus on the meaning and purpose of research; the development of a practice based research methodology; the myth, mist and missed opportunities of peer review and dissemination (including the disclosure of intellectual property); and the significance of funding.

The Biospheric Project - Manchester International Festival 2013:Technical food systems

The Biospheric Project is a nested multi-scalar urban agriculture project that aims to develop sustainable food systems in disadvantaged communities, though not only physical interventions, such as the urban masterplan and neighbourhood design to the building and its roof and façade, but also through social and commercial interventions, such as community involvement, businesses and a distribution system.

The project is focused around the Biospheric Foundation, a community interest company and research think-tank whose aim is to hasten our transition to a closed cycle, low-carbon economy. Its home is Irwell house, that houses a large-scale aquaponic-based food production system, which is directly linked to a whole-food shop (78 Steps, named after the distance from the productive system) and a whole food distribution system (the Whole Box). The building sits within a post-industrial landscape which is being developed into a new productive landscape, utilizing the the technologies developed by the Biospheric Foundation and Prof Greg Keeffe of Queens University Belfast. The collaboration links designer, academics and activists across the disciplines of Urban design, Architecture, Permaculture, landscape design, environmental science and business and community.

Sports Law

The term sports law is fourfold in nature and encompasses: (a) traditional areas of law, such as contract, tort, criminal, administrative and EU law, as applied to disputes of a sporting origin; (b) the particular impact that a range of statutory provisions might have on sport; for example, legislation governing discriminatory and unsafe practices in a workplace or monopolistic or fraudulent behaviour in an industry; (c) issues of public and social policy otherwise influencing the legislature and the courts, from the allocation of resources to the allocation of risk; and (d) lex sportiva, where that term is taken to reflect the various internal administrative regulations and awards by dispute-resolving mechanisms in sport. As a matter of practice, sports law tends to be concerned with the application of contract and commercial law principles to professional sport - and namely the application of such branches of law to disputes relating to the following "three pillars" of modern, professional sport i.e., disputes relating to the payment, sponsorship or endorsement of those who play sport for a living; disputes arising from decisions made by sports governing bodies; and disputes arising from the application of law to the holding of sports events.

Ultra-Wideband Communications - An idea whose time has still yet to come? [Wireless Corner]

This paper presents a critical analysis of ultrawideband (UWB) and considers the turbulent journey it has had from the Federal Communications Commission's bandwidth allocation in 2002 to today. It analyzes the standards, the standoffs, and the stalemate in standardization activities and investigates the past and present research and commercial activities in realizing the UWB dream. In this paper, statistical evidence is presented to depict UWB's changing fortunes and is utilized as an indicator of future prominence. This paper reviews some of the opinions and remarks from commentators and analyzes predictions that were made. Finally, it presents possible ways forward to reignite the high-data-rate UWB standardization pursuit.

Molecular dynamics simulation (MDS) to study nanoscale machining processes

Molecular Dynamics Simulations (MDS) are constantly being used to make important contributions to our fundamental understanding of material behaviour, at the atomic scale, for a variety of thermodynamic processes. This chapter shows that molecular dynamics simulation is a robust numerical analysis tool in addressing a range of complex nanofinishing (machining) problems that are otherwise difficult or impossible to understand using other methods. For example the mechanism of nanometric cutting of silicon carbide is influenced by a number of variables such as machine tool performance, machining conditions, material properties, and cutting tool performance (material microstructure and physical geometry of the contact) and all these variables cannot be monitored online through experimental examination. However, these could suitably be studied using an advanced simulation based approach such as MDS. This chapter details how MD simulation can be used as a research and commercial tool to understand key issues of ultra precision manufacturing research problems and a specific case was addressed by studying diamond machining of silicon carbide. While this is appreciable, there are a lot of challenges and opportunities in this fertile area. For example, the world of MD simulations is dependent on present day computers and the accuracy and reliability of potential energy functions [109]. This presents a limitation: Real-world scale simulation models are yet to be developed. The simulated length and timescales are far shorter than the experimental ones which couples further with the fact that contact loading simulations are typically done in the speed range of a few hundreds of m/sec against the experimental speed of typically about 1 m/sec [17]. Consequently, MD simulations suffer from the spurious effects of high cutting speeds and the accuracy of the simulation results has yet to be fully explored. The development of user-friendly software could help facilitate molecular dynamics as an integral part of computer-aided design and manufacturing to tackle a range of machining problems from all perspectives, including materials science (phase of the material formed due to the sub-surface deformation layer), electronics and optics (properties of the finished machined surface due to the metallurgical transformation in comparison to the bulk material), and mechanical engineering (extent of residual stresses in the machined component) [110]. Overall, this chapter provided key information concerning diamond machining of SiC which is classed as hard, brittle material. From the analysis presented in the earlier sections, MD simulation has helped in understanding the effects of crystal anisotropy in nanometric cutting of 3C-SiC by revealing the atomic-level deformation mechanisms for different crystal orientations and cutting directions. In addition to this, the MD simulation revealed that the material removal mechanism on the (111) surface of 3C-SiC (akin to diamond) is dominated by cleavage. These understandings led to the development of a new approach named the “surface defect machining” method which has the potential to be more effective to implement than ductile mode micro laser assisted machining or conventional nanometric cutting.

Sustainable non-automotive vehicles: The simulation challenges

Simulation is a well-established and effective approach to the development of fuel-efficient and low-emissions vehicles in both on-highway and off-highway applications.

The simulation of on-highway automotive vehicles is widely reported in literature, whereas research relating to non-automotive and off-highway vehicles is relatively sparse. This review paper focuses on the challenges of simulating such vehicles and discusses the differences in the approach to drive cycle testing and experimental validation of vehicle simulations. In particular, an inner-city diesel-electric hybrid bus and an ICE (Internal Combustion Engine) powered forklift truck will be used as case studies.

Computer prediction of fuel consumption and emissions of automotive vehicles on standardised drive cycles is well-established and commercial software packages such as AVL CRUISE have been specifically developed for this purpose. The vehicles considered in this review paper present new challenges from both the simulation and drive-cycle testing perspectives. For example, in the case of the forklift truck, the drive cycles involve reversing elements, variable mass, lifting operations, and do not specify a precise velocity-time profile. In particular, the difficulties associated with the prediction of productivity, i.e. the maximum rate of completing a series of defined operations, are discussed. In the case of the hybrid bus, the standardised drive cycles are unrepresentative of real-life use and alternative approaches are required in the development of efficient and low-emission vehicles.

Two simulation approaches are reviewed: the adaptation of a standard automotive vehicle simulation package, and the development of bespoke models using packages such as MATLAB/Simulink.

Nicotinamide Riboside Is a Major NAD+ Precursor Vitamin in Cow Milk

Background: Nicotinamide riboside (NR) is a recently discovered NAD+ precursor vitamin with a unique biosynthetic pathway. Although the presence of NR in cow milk has been known for more than a decade, the concentration of NR with respect to the other NAD+ precursors was unknown.

Objective: We aimed to determine NAD+ precursor vitamin concentration in raw samples of milk from individual cows and from commercially available cow milk.

Methods: LC tandem mass spectrometry and isotope dilution technologies were used to quantify NAD+ precursor vitamin concentration and to measure NR stability in raw and commercial milk. Nuclear magnetic resonance (NMR) spectroscopy was used to test for NR binding to substances in milk.

Results: Cow milk typically contained ∼12 μmol NAD+ precursor vitamins/L, of which 60% was present as nicotinamide and 40% was present as NR. Nicotinic acid and other NAD+ metabolites were below the limits of detection. Milk from samples testing positive for Staphylococcus aureus contained lower concentrations of NR (Spearman ρ = −0.58, P = 0.014), and NR was degraded by S. aureus. Conventional milk contained more NR than milk sold as organic. Nonetheless, NR was stable in organic milk and exhibited an NMR spectrum consistent with association with a protein fraction in skim milk.

Conclusions: NR is a major NAD+ precursor vitamin in cow milk. Control of S. aureus may be important to preserve the NAD+ precursor vitamin concentration of milk.