1,161 research outputs found

    Modelling and control of a variable-speed switched reluctance generator based wind turbine

    Get PDF
    This paper studies the system modelling and control aspects of switched reluctance generator (SRG) based variable speed wind turbines. A control system is implemented to provide proper operation of the SRG as well as power tracking capabilities for varying wind speeds. The control system for the grid side inverter that will allow the SRG to properly generate power to the system is also presented. Studies are presented of both the SRG and inverter control systems capabilities during a balanced three-phase fault. The paper will demonstrate that the SRG based wind turbine presents a feasible variable wind speed solution with good fault response capabilities

    New political actors in Europe: Beppe Grillo and the M5S

    Get PDF
    New social and political movements from radically different political positions are emerging across Europe using social media, posing a new challenge to existing political parties and structures. The Pirate Party in Germany and the Occupy movement are examples of movements that have employed social media to grow rapidly and create a significant political and social impact – all in the last three years. Beppe Grillo, the Italian comedian and blogger, is one of the first political figures to have embraced this change. He has used social media to communicate, recruit and organise, growing the Moviment 5 Stelle from practically nothing to a major political force in Italy in the space of three years, with it expected to play a crucial role in the 2013 Italian elections. His anti-establishment message has resonated with many against a backdrop of declining trust in political institutions, falling political party membership and ever-lower voter turnout. This report presents the results of a survey of 1,865 Facebook fans of Beppe Grillo and the Movimento 5 Stelle. It includes data on who they are, what they think, and what motivates them to shift from virtual to real-world activism. It also compares them with other similar parties in Western Europe and their attitudes to those of the Italian population. This report is the seventh in a series of country specific briefings about the online support of populist parties across Europe

    Solar total and spectral irradiance reconstruction over the last 9000 years

    Get PDF
    Changes in solar irradiance and in its spectral distribution are among the main natural drivers of the climate on Earth. However, irradiance measurements are only available for less than four decades, while assessment of solar influence on Earth requires much longer records. The aim of this work is to provide the most up-to-date physics-based reconstruction of the solar total and spectral irradiance (TSI/SSI) over the last nine millennia. The concentrations of the cosmogenic isotopes 14C and 10Be in natural archives have been converted to decadally averaged sunspot numbers through a chain of physics-based models. TSI and SSI are reconstructed with an updated SATIRE model. Reconstructions are carried out for each isotope record separately, as well as for their composite. We present the first ever SSI reconstruction over the last 9000 years from the individual 14C and 10Be records as well as from their newest composite. The reconstruction employs physics-based models to describe the involved processes at each step of the procedure. Irradiance reconstructions based on two different cosmogenic isotope records, those of 14C and 10Be, agree well with each other in their long-term trends despite their different geochemical paths in the atmosphere of Earth. Over the last 9000 years, the reconstructed secular variability in TSI is of the order of 0.11%, or 1.5 W/m2. After the Maunder minimum, the reconstruction from the cosmogenic isotopes is consistent with that from the direct sunspot number observation. Furthermore, over the nineteenth century, the agreement of irradiance reconstructions using isotope records with the reconstruction from the sunspot number by Chatzistergos et al. (2017) is better than that with the reconstruction from the WDC-SILSO series (Clette et al. 2014), with a lower chi-square-value

    Mystical orientation and the perceiving process : a study among Anglican clergymen

    Get PDF
    This study examines the hypothesised link between mystical orientation and the perceiving process within the Jungian model of psychological type. Data were provided by 232 Anglican clergymen serving in the Church in Wales who completed both the Francis-Louden Mystical Orientation Scale and the Francis Psychological Type Scales. The data demonstrated that intuitive types recorded significantly higher scores than sensing types on the index of mystical orientation, supporting the hypothesis based on Ross' thesis

    Clustering of Pseudomonas aeruginosa transcriptomes from planktonic cultures, developing and mature biofilms reveals distinct expression profiles

    Get PDF
    BACKGROUND: Pseudomonas aeruginosa is a genetically complex bacterium which can adopt and switch between a free-living or biofilm lifestyle, a versatility that enables it to thrive in many different environments and contributes to its success as a human pathogen. RESULTS: Transcriptomes derived from growth states relevant to the lifestyle of P. aeruginosa were clustered using three different methods (K-means, K-means spectral and hierarchical clustering). The culture conditions used for this study were; biofilms incubated for 8, 14, 24 and 48 hrs, and planktonic culture (logarithmic and stationary phase). This cluster analysis revealed the existence and provided a clear illustration of distinct expression profiles present in the dataset. Moreover, it gave an insight into which genes are up-regulated in planktonic, developing biofilm and confluent biofilm states. In addition, this analysis confirmed the contribution of quorum sensing (QS) and RpoS regulated genes to the biofilm mode of growth, and enabled the identification of a 60.69 Kbp region of the genome associated with stationary phase growth (stationary phase planktonic culture and confluent biofilms). CONCLUSION: This is the first study to use clustering to separate a large P. aeruginosa microarray dataset consisting of transcriptomes obtained from diverse conditions relevant to its growth, into different expression profiles. These distinct expression profiles not only reveal novel aspects of P. aeruginosa gene expression but also provide a growth specific transcriptomic reference dataset for the research community

    Broadband laser cooling of trapped atoms with ultrafast pulses

    Full text link
    We demonstrate broadband laser cooling of atomic ions in an rf trap using ultrafast pulses from a modelocked laser. The temperature of a single ion is measured by observing the size of a time-averaged image of the ion in the known harmonic trap potential. While the lowest observed temperature was only about 1 K, this method efficiently cools very hot atoms and can sufficiently localize trapped atoms to produce near diffraction-limited atomic images

    Conviviality and Parallax in David Olusoga’s Black and British: A Forgotten History

    Get PDF
    Through examining the BBC television series, Black and British: A Forgotten History, written and presented by the historian David Olusoga, and in extending Paul Gilroy’s assertion that the everyday, banality of living with difference is now an ordinary part of British life, this article considers how Olusoga’s historicization of the black British experience reflects a convivial rendering of UK multiculture. In particular, when used alongside Žižek’s notion of parallax, it is argued that understandings of convivial culture can be supported by a historical importance that deliberately ‘shocks’ and, subsequently dislodges, popular interpretations of the UK’s ‘white past’. Notably, it is parallax which puts antagonism, strangeness and ambivalence at the heart of contemporary depictions of convivial Britain, with the UK’s cultural differences located in the ‘gaps’ and tensions which characterize both its past and present. These differences should not be feared but, as a characteristic part of our convivial culture, should be supplemented with historical analyses that highlight but, also, undermine, the significance of cultural differences in the present. Consequently, it is suggested that if the spontaneity of conviviality is to encourage openness, then, understandings of multiculturalism need to go beyond reification in order to challenge our understandings of the past. Here, examples of ‘alterity’ are neither ‘new’ nor ‘contemporary’ but, instead, constitute a fundamental part of the nation’s history: of the ‘gap’ made visible in transiting past and present
    corecore