3,741 research outputs found
R.M. Simmons presentation, Rena Smart book review
No full textR.M. Simmons of the Gospel Music Workshop of America gives a presentation on the African influence in the African American religious experience. He explains how African slaves brought to America their concept of music (utilitarian concept of music). Simmons further discusses the fusion between the utilitarian concept and the Western concept of religion resulting in spirituals. He also describes hymn categories in early forms of formal African American worship experiences. Simmons takes questions from the audience among which is Dr. Riggins Earl Jr. Video concludes with a book review on Christian Theology and Ethics by Rena Smart.The Atlanta University Center Robert W. Woodruff Library acknowledges the generous support of the National Endowment for Humanities - Humanities Collections and Reference Resources Implementation Project Grant in supporting the processing and digitization of a number of its major archival collections as part of the project: Spreading the Word: Expanding Access to African American Religious Archival Collections at the Atlanta University Center Robert W. Woodruff Library.</em
Velocity-Gradient Probability Distribution Functions in a Lagrangian Model of Turbulence
No full textThe Recent Fluid Deformation Closure (RFDC) model of lagrangian turbulence is recast in path-integral language within the framework of the Martin-Siggia-Rose functional formalism. In order to derive analytical expressions for the velocity-gradient probability distribution functions (vgPDFs), we carry out noise renormalization in the low-frequency regime and find approximate extrema for the Martin-Siggia-Rose effective action. We verify, with the help of Monte Carlo simulations, that the vgPDFs so obtained yield a close description of the single-point statistical features implied by the original RFDC stochastic differential equations
Transferência eletrônica em sistemas moleculares
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Física, Florianópolis, 2012O presente trabalho apresenta uma análise teórica do fenômeno de transferência eletrônica (ET) para dois sistemas moleculares. Inicialmente é apresentada uma breve introdução sobre o processo de transferência eletrônica, seguida de uma descrição de seu papel em dispositivos fotovoltaicos orgânicos e poliméricos. Prossegue-se com uma descrição detalhada da teoria usada nesta dissertação e das diferentes técnicas computacionais utilizadas para realizar a propagação temporal de pacotes de onda eletrônicos em sistemas moleculares. Dois modelos físicos são investigados pelo formalismo. No primeiro caso apresenta-se uma análise do fenômeno de transferência eletrônica em um sistema doador-aceitador assistido por ponte: dois átomos de berílio atuam como o par doado-aceitador, para os quais a transferência é intermediada por uma estrutura molecular rígida (cadeia de polietileno) C17H36. Examinou-se as consequência para a transferência dos diferentes comprimentos de ligação que conectam doador e aceitador com a ponte, e a variação do número de unidades de etileno na ponte. Os cálculos demonstram a transição entre a transferência de carácter ôhmico e a super-trânsferência, em acordo com outros formalismos. O segundo modelo de estudo consiste de uma cadeia triatômica dinâmica idealizada para a investigação dos efeitos do movimento iônico sobre a dinâmica eletrônica. Fica evidenciado que em frequências nucleares baixas a dinâmica eletrônica é de carácter adiabático. Em contrapartida, frequências maiores conduzem à efeitos de carácter não adiabático.Abstract : This work presents a theoretical analysis of the electron transfer process for two types of molecular systems. It begins with a brief introduction about the electron transfer process, which is followed by a discussion about the relevance of the process to the operation of organic and polymeric photovoltaic devices. In the sequence, the relevant theory is explained in detail, particularly the computational methods that are used to time propagate electronic wavepackets in molecular structures. Two physical models are investigated with the formalism. In the first case, the analysis of the electron transfer mechanism is carried for a donor-acceptor system coupled by a bridge: two beryllium atoms act as the donor-acceptor pair, and the electronic transfer takes place through a rigid molecular structure (polyethylene chain) C17H36. The effects caused by changing bond lengths between donor/acceptor sites and the bridge as well as varying the number of ethylene units in the bridge were investigated. The calculations show a transition of the transfer behaviour from ohmic to super-exchange, in accordance with predictions made by different formalisms. The second model system consists of a tri-atomic dynamic chain, which is thought for studying the effects of the ionic motion on the electronic dynamics. The present study shows that the electronic dynamics is adiabatic at low nuclear frequencies whereas at high nuclear frequencies non-adiabatic effects arise
Author Correction: Global geochemical fingerprinting of plume intensity suggests coupling with the supercontinent cycle
No full textThe original version of this Article omitted from the author list the 4th and 5th authors, Grant Cox and Ross Mitchell, who were both at Curtin University. Consequently, the corrected version of the Acknowledgements removes the following from the original version: ‘and Ross Mitchell’. In addition, the following was added to the Author Contributions: ‘G.M.C. and R.M. were involved in an early attempt of this study.’. This has been corrected in both the PDF and HTML versions of the Article
Colonising "The Coral Island": A Postcolonial Reading of R.M. Ballantyne's Children's "Classic"
No full textstudent essayBeing written during the rise of the British Empire in the 1850sm R.M. Ballantyne's boys' adventure story "The Coral Island" is in many ways a product of its time, conveying imperial ideas and Victorian values to the young reader. Through his portrayal of the native inhabitants in relation to his descriptions of the three British protagonists, the author creates a stereotyped image of the natives as primitive savages. Due to the further use of a first person narrator and realist pretensions, the dated racist ideas become influential upon the reader. In spite of the fact that the novel has been considered as an entertaining children's classic by generations since its first publication, "The Coral Island" should not be classified as good children's literature today but should rather be historicised as a result of its controversial contents. By adopting a postcolonial approach and applying postcolonial theory in my analysis of R.M. Ballantyne's "The Coral Island", I have in this essay endeavoured to demonstrate in what ways the novel would prove problematic as a children's book today. In my first chapter I present the imperial ideas and Victorian values that are conveyed, whereas in my second chapter I discuss Ballantyne's stereotyping of the natives. As a result of my study of this novel, I have exemplified how the author portrays the three British boys as representative of the Victorian ideals of the time. I have also illustrated their assumed superiority over nature and their roles as colonisers. Furthermore, my analysis of "The Coral Island" has revealed how Ballantyne communicates both white superiority as well as the Western "oblibation" to civilise primitive people throug Christian conversion. Consequently, the novel promotes the ideology of its time. As a result of my findings, I would like to argue that "The Coral Island" should today be viewed as a text conveying historical ideas and values rather than as an exciting children's classic
Acoustic emmission gedrag van verschillende grondsoorten
No full textDit rapport vat de resultaten samen van de meetrapporten "Acoustic Emission" (A.E.) gedrag van verschillende grondsoorten door ing. F.M. Schenkeveld, LGM en "Acoustic emission laboratory testing of sand, clay and peat soils" door Prof. R.M. Koerner, Drexel University, U.S.A. Het onderzoek werd verricht in opdracht van het Centrum voor Onderzoek Waterkeringen (COW), in samenwerking met het Laboratorium voor Grondmechanica (LGM). Projectleider voor het COW was ir. A. Penning. Het doel van het onderzoek is de evaluatie van de "acoustic emission"-methode met betrekking tot stabiliteitsproblemen bij Nederlandse dijken. Tijdens het vooronderzoek is kontakt gelegd met Prof. R.M. Koerner (R.M.K.), Drexel University, U.S.A. Om een goede basis te geven aan het onderzoek werd met Prof. Koerner een gezamenlijk project uitgevoerd. "Acoustic Emissions" zijn spanningsgolven die gegenereerd worden in een materiaal onder spanning tijdens deformatie. Soms zijn deze spanningsgolven hoorbaar (kraken van hout), maar vaak niet vanwege de lage amplitude en hoge frequentie. Een piezoelectrische sensor wordt gebruikt om de "acoustic emissions" te detecteren. De opnemer produceert een electrisch signaal evenredig met de amplitude van de waargenomen trilling. Het signaal wordt dan versterkt, gefilterd en geteld of op een andere wijze gekwantificeerd. Achtergrondruis en andere ongewenste verstoringen worden gefilterd of apart gekwantificeerd en afgetrokken van de resultaten. De tellingen of andere bewerkte resultaten van de emissies worden dan gecorreleerd met het materiaal gedrag om empirisch de veiligheid van de onderzochte situatie te bepalen. Indien er geen acoustic emissions zijn is het materiaal in het algemeen in rust en stabiel. Evenwel als er emissies worden waargenomen is het materiaal in beweging, hetgeen uiteindelijk kan leiden tot bezwijken. De komponenten van het huidige "acoustic emission" systeem bestaan uit: een stalen staaf (om het signaal vanuit de grond naar een geschikt waarnemingspunt te brenger.) , een sensor (geofoon, versnellingsopnemer,hydrofoon of een andere opnemer die een mechanische trilling in een electrisch signaal omzet), een voorversterker (om het signaal te versterken indien een lange kabel wordt gebruikt), filters (om ongewenste gedeelten van het signaal te elimineren), een versterker (om het signaal verder te versterken voor signaalbewerking) en een signaalbewerkingssysteem. Het signaalbewerkingssysteem is over het algemeen een teller die telt als een bepaalde drempelwaarde wordt overschreden.TAW/EN
Value of Information Based Design of Control Software
No full textElectrical Engineering, Mathematics and Computer Scienc
Algorithms for non-parametric Bayesian belief nets
No full textElectrical Engineering, Mathematics and Computer Scienc
High dimensional dependence: Copulae, sensitivity, sampling
No full textElectrical Engineering, Mathematics and Computer Scienc
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