One Dimensional Modeling of a Turbogenerating Spark Ignition Engine Operating on Biogas

Turbocompounding is generally regarded as the process of recovering a proportion of the exhaust gas energy from a reciprocating engine and applying it to the output power of the crankshaft. In conventional turbocompounding, the power turbine has been mechanically connected to the crankshaft but now a new method has emerged. Recent advances in high speed electrical machines have enabled the power turbine to be coupled to an electric generator. Decoupling the power turbine from the crankshaft and coupling it to a generator allows the power electronics to control the turbine speed independently in order to optimize the turbine efficiency for different engine operating conditions.

The Senses of Muriel Rukeyser’s The Book of the Dead

When Muriel Rukeyser travelled to Gauley Bridge in 1936 to report on the industrial disaster that had led to the deaths of over 700 miners, her findings led her to write what is arguably her masterpiece – the 1938 poem series The Book of the Dead. Of all Rukeyser's writings, this hybrid work of documentary techniques and metaphors, of testimony and elegy, has attracted the most critical attention. However, analyses of the series have tended to focus on the ways in which the poet adopted and adapted documentary methods in order to offer a leftist ideological critique on capitalist-born social injustice. The purpose of this article is not to negate such readings, but to offer alongside them insight into a more ethical-philosophical approach that I believe guided Rukeyser's entire career. Via an examination of the ways in which Rukeyser employs the human senses to articulate the complexities of human political, metaphysical and social relations, this article explores the influence of the Zionist Martin Buber on the poet. Rukeyser acknowledged Buber's writings in her later work, but I contend here that they played a large part in the formation of her poetics, especially in connection with her documentary aesthetic. Whilst several critics have noted, albeit often superficially, the Marxist flavour of Rukeyser's poetry in The Book of the Dead, I argue for the influence of Buber over Marx in terms or responsibility, community and dialogue. Both Rukeyser's and Buber's methods of expressing and promoting these ethical necessities rely on a synaesthetic response to the world. Where Buber advances a dialogue between the self and alterity through transcendent personal encounter, Rukeyser locates such encounter in the poem, arguing for an exchange that leads to creation, and to personal and interpersonal growth.

‘Facing the Fact: Word and Image in Muriel Rukeyser’s “Worlds Alongside”’

This essay explores an example of a little-known, yet highly significant part of Rukeyser’s early oeuvre: the magazine photo-narrative. Profoundly engaged with the documentary expression of the 1930s, Rukeyser utilised the genre’s methods, aesthetics and images to create a hybrid text reporting the realities of the Depression in lyrical, imaginative terms. The result is a conflation of what Rukeyser understood to constitute poetry, and therefore life: the document and the unverifiable fact, presented in an innovative format that is shaped by Rukeyser’s ethical poetics of connection to construct lessons in creative exchange and being in the world.

The spark of life:The role of electric fields in regulating cell behaviour using the eye as a model system

Endogenous electric fields (EF) have long been known to influence cell behaviour during development, neural cell tropism, wound healing and cell behaviour generally. The effect is based on short circuiting of electrical potential differences across cell and tissue boundaries generated by ionic segregation. Recent in vitro and in vivo studies have shown that EF regulate not only cell movement but orientation of cells during mitosis, an effect which may underlie shaping of tissues and organs. The molecular basis of this effect is founded on receptor-mediated cell signalling events and alterations in cytoskeletal function as revealed in studies of gene deficient cells. Remarkably, not all cells respond directionally to EF in the same way and this has consequences, for instance, for lens development and vascular remodelling. The physical basis of EF effect may be related to changes induced in 'bound water' at the cell surface, whose organisation in association with trans-membrane proteins (e.g. receptors) is disrupted when EF are generated. Copyright © 2007 S. Karger AG.

'Easter Rising', 1914-1918-online. International Encyclopedia of the First World War

Although a military failure, the 1916 rebellion transformed Ireland by destroying the possibility of a political settlement between Irish nationalists and the British state and by popularising a republican movement prepared to use violence to achieve independence. This essay surveys the political background to the Easter Rising, its planning, the motivations and ideology of the rebels and the battle for Dublin. It concludes by assessing the Rising’s political impact and briefly summarising historiographical interpretations and commemorative trends. It argues that the origins, conduct, impact and aftermath of the insurrection are best understood within the wider context of the First World War.

Mechanical behaviour of AISiC nano composites produced by Ball Milling and Spark Plasma Sintering

Neste trabalho foram produzidos nanocompósitos de AlSiC misturando alumínio puro com nano partículas de SiC com diâmetro de 45 – 55 nm, usando, de forma sequencial, a técnica da metalurgia do pó e a compactação por “ Spark Plasma Sintering”. O compósito obtido apresentava grãos com 100 nm de diâmetro, encontrandose as partículas de SiC localizadas, principalmente, nas fronteiras de grão. O nanocompósito sob a forma de provetes cilíndricos foi submetido a testes de compressão uniaxial e a testes de nanoindentação para analisar a influência das nanopartículas de SiC, da fração volúmica de ácido esteárico e do tempo de moagem, nas propriedades mecânicas do material. Para efeitos de comparação, utilizouse o comportamento mecânico do Al puro processado em condições similares e da liga de alumínio AA1050O. A tensão limite de elasticidade do nanocompósito com 1% Vol./Vol. de SiC é dez vezes superior à do AA1050. O refinamento de grão à escala nano constitui o principal mecanismo de aumento de resistência mecânica. Na realidade, o Al nanocristalino sem reforço de partículas de SiC, apresenta uma tensão limite de elasticidade sete vezes superior à da liga AA1050O. A adição de 0,5 % Vol./Vol. e de 1 % Vol./Vol. de SiC conduzem, respetivamente, ao aumento da tensão limite de elasticidade em 47 % e 50%. O aumento do tempo de moagem e a adição de ácido esteárico ao pó durante a moagem conduzem apenas a um pequeno aumento da tensão de escoamento. A dureza do material medida através de testes de nanoindentação confirmaram os dados anteriores. A estabilidade das microestruturas do alumínio puro e do nanocompósito AlSiC, foi testada através de recozimento de restauração realizado às temperaturas de 150 °C e 250 °C durante 2 horas. Aparentemente, o tratamento térmico não influenciou as propriedades mecânicas dos materiais, excepto do nanocompósito com 1 % Vol./Vol. de SiC restaurado à temperatura de 250 °C, para o qual se observou uma redução da tensão limite de elasticidade na ordem dos 13 %. No alumínio nanocristalino, a tensão de escoamento é controlada pelo efeito de HallPetch. As partículas de SiC, são segregadas pelas fronteiras do grão e não contribuem para o aumento de resistência mecânica segundo o mecanismo de Orowan. Alternativamente, as nanopartículas de SiC constituem um reforço das fronteiras do grão, impedindo o seu escorregamento e estabilizando a nanoestrutura. Deste modo, as propriedades mecânicas do alumínio nanocristalino e do nanocompósito de AlSiC poderão estar relacionadas com a facilidade ou dificuldade do escorregamento das fronteiras de grão, embora não seja apresentada prova explícita deste mecanismo à temperatura ambiente.