795 research outputs found
Convective shutdown in a porous medium at high Rayleigh number
No full textConvection in a closed domain driven by a dense buoyancy source along the upper boundary soon starts to wane owing to the increase of the average interior density. In this paper, theoretical and numerical models are developed of the subsequent long period of shutdown of convection in a two-dimensional porous medium at high Rayleigh number Ra\mathit{Ra}. The aims of this paper are twofold. Firstly, the relationship between this slowly evolving ‘one-sided’ shutdown system and the statistically steady ‘two-sided’ Rayleigh–Bénard (RB) cell is investigated. Numerical measurements of the Nusselt number Nu\mathit{Nu} from an RB cell (Hewitt et al., Phys. Rev. Lett., vol. 108, 2012, 224503) are very well described by the simple parametrization Nu=2.75+0.0069Ra\mathit{Nu}= 2. 75+ 0. 0069\mathit{Ra}. This parametrization is used in theoretical box models of the one-sided shutdown system and found to give excellent agreement with high-resolution numerical simulations of this system. The dynamical structure of shutdown can also be accurately predicted by measurements from an RB cell. Results are presented for a general power-law equation of state. Secondly, these ideas are extended to model more complex physical systems, which comprise two fluid layers with an equation of state such that the solution that forms at the (moving) interface is more dense than either layer. The two fluids are either immiscible or miscible. Theoretical box models compare well with numerical simulations in the case of a flat interface between the fluids. Experimental results from a Hele-Shaw cell and numerical simulations both show that interfacial deformation can dramatically enhance the convective flux. The applicability of these results to the convective dissolution of geologically sequestered CO2{\mathrm{CO} }_{2} in a saline aquifer is discussed
Revisiting Tony Price’s (1979) account of the native vegetation of Duck River and Rookwood Cemetery, western Sydney
No full textThe Duck River Reserve and Rookwood Cemetery in the highly urbanised Auburn district of western-Sydney hold small but botanically valuable stands of remnant native vegetation. In the late 1970s, local resident G.A.-(Tony) Price, recognised the value of these remnants, both for the species they held and the clues they could give us-to the past, and spent three years surveying and collecting plants at these sites. Price recorded the species present and-their abundance, and described the habitats in which they were found. He observed the ecology of plant interactions,-moisture, shading and fire response, interpolating them into a picture of the landscape and vegetation of the district-prior to European settlement. At a time when field botany was inaccessible to many, and the focus of conservation was-largely on the broader scale, Price’s local scale work at these sites was unusual and important. Though never formally-published, Price’s 1979 account ‘The Vegetation of Duck River and Rookwood Cemetery, Auburn’ has been cited in-all subsequent work of consequence for the area. This paper presents and reviews Price’s work and discusses his-observations in relation to the current vegetation of these areas. Tony Price’s contributions also highlight the value and-role that ordinary citizens can play alongside professional botanists and plant ecologists in long term data collection,-considered observation and environmental management. A copy of Price’s original unpublished account has been-included as an appendix to this paper
Estudo do escoamento imiscível água/óleo mediante experimentação em célula de Hele-Shaw e simulação CFD
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia QuímicaO estudo de sistemas água-óleo é de fundamental importância para diversos processos industriais. Procedimentos como a recuperação secundária de petróleo e o bombeamento de óleos de viscosidade elevada, mediante a injeção conjunta de água, exemplificam situações na indústria petrolífera em que o comportamento da interface água-óleo traz importantes conseqüências para a eficiência da produção. Também nos casos de vazamentos a partir de dutos submersos, e na contaminação de águas subterrâneas pela proximidade de uma fase óleo, os aspectos fenomenológicos desse sistema imiscível devem ser conhecidos a fim de que medidas adequadas de remediação e quantificação dos danos ambientais possam ser postos em prática. O fato de o petróleo ser, de um modo geral, mais viscoso e menos denso que a água faz com que, no escoamento simultâneo desses dois fluidos, a água apresente a tendência de se deslocar com maior velocidade em relação ao óleo. Como conseqüência, dependendo das diferenças de viscosidades e densidades entre os dois fluidos, além das forças de tensão interfacial, pode vir a ocorrer o fenômeno de digitação viscosa. Assim, no deslocamento de óleo por injeção de água, fingers gerados a partir da fase água podem penetrar na fase óleo, ocasionando um retardamento no deslocamento do óleo com saída antecipada da água, o que representa um prejuízo para a operação. Uma ferramenta de simulação fluidodinâmica, apta a descrever corretamente os fenômenos e padrões de escoamento de um sistema águaóleo, sob diferentes condições operacionais, pode se constituir em notável instrumento para aprofundar conhecimentos da fenomenologia envolvida e, também, gerar elementos de inovação tecnológica para as diferentes aplicações Neste trabalho, explora-se o comportamento de um sistema água-óleo através de um modelo tridimensional de uma célula de Hele-Shaw. Esse modelo reproduz uma célula real carregada com água e óleo com dimensões de 100 cm de comprimento por 30 cm de largura, com espaçamento típico entre as placas de 0,10 cm. Uma série de ensaios computacionais foram realizados para validar o modelo, além dos critérios usuais de estabilidade numérica e fechamento de balanços. O modelo computacional da célula de Hele-Shaw, possibilitou a observação do comportamento da interface. As propriedades dos fluídos (densidade, viscosidade e tensão superficial) e fenômenos físicos (temperatura, capilaridade, força gravitacional e velocidade de injeção do fluído) influenciaram diretamente na resposta do sistema. Através de simulações computacionais foi possível estudar individualmente a importância e efeito que cada fator exerce sobre o sistema, desde as propriedades dos fluidos até as condições de contorno aplicadas, foi possível também, identificar o grau de atuação das forças interfaciais, gravitacional e do arraste viscoso, levando ao surgimento do fenômeno de digitação viscosa. Comprovou-se que o aumento das forças capilares costuma levar a um aumento da instabilidade, com conseqüente aumento no número de fingers desenvolvidos, aumentando a área de óleo em atraso e reduzindo a eficiência do processo. The study of systems water-oil is of fundamental importance for several industrial processes. Procedures as the secondary recovery of petroleum and the pum situations in the industry of petroleum where the behavior of the interface wateroil brings important consequences for the efficiency of the production. Also in the cases where happen leaks starting from ducts submerged, and in cases of contamination of underground waters for the proximity of a phase oil, the aspects of phenomena of that system immiscible should be known so that appropriate measures of recovery and quantification of the environmental damages can be put into practice. The fact of the petroleum to be, in general, more viscous and less dense than the water does with that, in the simultaneous drainage of those two fluids, the water presents the tendency of moving with larger speed in relation to the oil. As consequence, depending on the differences of viscosities and densities among the two fluids, besides the forces of interface tension, it can come to happen the phenomenon of viscous fingering. Like this, in the oil displacement with injection of water, fingers generated starting from the phase water can penetrate in the phase oil, causing retardation in the displacement of the oil with premature exit of the water, what represents damage for the operation. A tool CFD # Computational Fluid Dynamics, capable to describe the phenomena and patterns of drainage of a system water-oil correctly, under different operational conditions, it can be constituted in notable instrument to deepen knowledge of the involved phenomenology and, also, to generate elements of technological innovation for the different applications. In this work, the behavior of a system water-oil is explored through a 3D model of a cell of Hele-Shaw. That model reproduces a real cell loaded with water and oil with dimensions of 100 cm of length for 30 cm of width, with typical spacing among the plates of 0,10 cm. A series of rehearsals computation was accomplished to validate the model, besides the usual criteria of numeric stability and closing of swingings. The computational model of the cell of Hele-Shaw, made possible the observation of the behavior of the interface. The properties of those flowed (density, viscosity and tension surface) and physical (temperature, capillarity, forces gravitational and speed of injection of the flowed) phenomena influenced directly in the answer of the system. Through computational simulations it was possible to study the importance and effect that each factor exercises on the system individually, from the properties of the fluids to the outline conditions applied, it was possible also, to identify the degree of performance of the interface forces, gravitational and of the it drags viscous, taking to the appearance of the phenomenon of viscous fingering. To prove that the increase of the capillary forces take the an increase of the instability, with consequent increase in the number of developed fingers, increasing the oil area in delay and reducing the efficiency of the process
The role of lawyers in strategic alliances (tape 2 of 3)
No full textSymposium presented on October 4, 2002. Symposium explores how lawyers can bargain effectively without impairing trust and devise contract terms that will enhance trust and cooperation to maximize the profitability of alliances. --program flyer. Introduction by Gerald Korngold, Dean of the School of Law; moderated by Professor George W. Dent, Jr.; Steven Fraidin and Rachelle C. Sampson, speakers; commentators Daniel F. Austin, Edward Bernstein, Jeanne M. Rickert, Hewitt B. Shaw, Jr., and Wendy C. Shiba
Contents: Strategic alliances and corporate control / Stephen Fraidin -- Alliance structure: selection and consequences / Rachelle C. Sampson -- Negotiating and drafting for strategic alliances / George W. Dent, J
Directional Footing, Degeneracy, and Alignment
No full textThis paper argues from an Optimality Theory perspective that no one-to-one correspondence exists between directional footing effects and individual constraints. Recent work in OT claims that directional footing effects are best captured by the constraints All-Feet-Left (Ft-Left) and All-Feet-Right (Ft-Right) in (1) (e.g. McCarthy & Prince 1993b, 1994; Kirchner 1993; Cohn & McCarthy 1994; Crowhurst & Hewitt, in press; Hewitt 1994a; Kager 1994).
(1) a. All-Feet-Left: Align(Foot, L, PrWd, L)
b. All-Feet-Right: Align(Foot, R, PrWd, R)
This paper argues that the relationship between the alignment constraints in (1) and directional footing is more complicated than has been envisioned. In fact, the OT account presented here reveals directional effects to be epiphenomenal: either of the constraints in (1) may yield rightward or leftward footing, depending on its interaction with constraints requiring syllable-to-foot parsing and binary foot structure (see below). We also show that directionality and stray syllable parsing at edges are dependent: right-to-left and left-to-right effects under Ft-Left dominance co-occur with either the presence or the absence of a degenerate foot, but not with both. This relationship is inverted when Ft-Right dominates Ft-Left. One outcome of this study is that interactions among a small number of constraints leads to a modified typological view of metrical patterns familiar from earlier work.The definitive version of this paper was published in NELS 25: Proceedings of the North East Linguistics Society (1995) and is available at http://glsa.hypermart.net/Crowhurst, M., & Hewitt, M. S. (1995). Directional footing, degeneracy, and alignment. In J. N. Beckman (Ed.), NELS 25: Proceedings of the North East Linguistics Society (pp. 47-61). Amherst, MA: GLSA (Graduate Linguistic Student Association), Dept. of Linguistics, University of Massachusetts
Music for classical guitar by South African composers : a historical survey, notes on selected works and a general catalogue
No full textIncludes abstract.Includes bibliographical references (leaves 296-309).This is the first comprehensive investigation of music for, or including, the classical guitar by South African composers. The focus of this research has been, firstly, to uncover as much of the repertoire as possible, and, secondly, to collate, study, catalogue and report on the information. A brief historical survey of the guitar in South Africa provides the context within which this study was conducted. The primary sources of quantitative data collection were through the archival catalogues of the South African Music Rights Organisation and through personal contact with guitarists, composers and guitar teachers. Other sources consulted were publishers, broadcasting corporations, recording companies, libraries and the internet. The body of the dissertation comprises biographical sketches, background notes, analyses and technical notes on 17 selected solo and chamber works dating from 1947 to 2007 by some of South Africa's most prominent composers and guitaristcomposers. The repertoire ranges in style from the traditional and ethnically inspired to the experimental and abstract. As this is an empirical survey, each selected entry includes details on instrumentation, duration, level of difficulty, number of pages, scordatura, commissions or requests, sources or publishers, premières and recordings. A biography of each composer is provided as well as background notes which offer an overview of the selected work. The notes discuss historical, cultural, musical and extra-musical influences, and frequently include references to interview material. The commentaries on the selected works, with musical examples, include an analytical component describing structure, form, stylistic and compositional elements, while the technical observations include performance suggestions and a grading for each work
The role of lawyers in strategic alliances (tape 1 of 3)
No full textSymposium presented on October 4, 2002. Symposium explores how lawyers can bargain effectively without impairing trust and devise contract terms that will enhance trust and cooperation to maximize the profitability of alliances. --program flyer. Introduction by Gerald Korngold, Dean of the School of Law; moderated by Professor George W. Dent, Jr.; Steven Fraidin and Rachelle C. Sampson, speakers; commentators Daniel F. Austin, Edward Bernstein, Jeanne M. Rickert, Hewitt B. Shaw, Jr., and Wendy C. Shiba
Contents: Strategic alliances and corporate control / Stephen Fraidin -- Alliance structure: selection and consequences / Rachelle C. Sampson -- Negotiating and drafting for strategic alliances / George W. Dent, J
An example concerning the Yosida-Hewitt decomposition of finitely additive measures
No full textLet
λ
\lambda
be Lebesgue measure on the Lebesgue
σ
\sigma
-algebra
L
\mathcal {L}
of
I
:=
]
0
,
1
[
I:=]0,1[
. The author gives an example of a purely finitely additive measure
φ
:
L
→
[
0
,
1
]
\varphi :\mathcal {L} \to [0,1]
vanishing on
λ
\lambda
-null sets such that
∫
f
d
φ
=
∫
f
d
λ
\smallint f\,d\varphi = \smallint f\,d\lambda
for every bounded continuous function f on I
(
f
∈
C
b
(
I
)
)
(f \in {C_b}(I))
. Consequently,
λ
−
φ
∈
L
∞
(
λ
)
′
\lambda - \varphi \in {L^\infty }(\lambda )’
annihilates
C
b
(
I
)
{C_b}(I)
and is not purely finitely additive, contrary to an assertion of Yosida and Hewitt.</p
Connecting Research with Communities through Performative Social Science
No full textA pioneer in Performative Social Science, Kip Jones makes a case for the potential of arts-based social science to reach audiences and engage communities. Jones contextualises both the use of the arts in Social Science, as well as the utility of Social Science in the Arts and Humanities. The discussion turns next to examples from his own work and what happens when Art talks to Social Science and Social Science responds to Art. The benefits of such interaction and interdisciplinarity are outlined in relation to a recently completed project using multi-methods, which resulted in the production of a professional short film. In conclusion, Performative Social Science is redefined in terms of synthesis that can break down old boundaries, open up channels of communication and empower communities through engagement
Art and counter-publics in Third Way cultural policy
No full textIn the UK, over the past decade, the rhetoric of ‘Third Way’ governance informed cultural policy. The research sets out how the agenda for cultural policy converged with priorities for economic and social policy, in policies implemented by Arts Council England, in the commissioning of publicly funded visual art and within culture-led regeneration. Hence visual art production was further instrumentalized for the purposes of marketization and privatization. The practice-based research examines the problems issues and contingencies for visual art production in this context.
Public sphere theory is used to examine ideas of publics and publicness in Third Way cultural policy context, in state cultural institutions and programming. Using Jürgen Habermas’ conception of the public sphere, the research proposes that cultural policy functioned as ‘steering media’, as publicity for the state to produce social cohesion and affirmative conceptions of the social order, i.e. the management of publics. In contrast, public sphere theory is concerned with societal processes of opinion formation, of selfforming, deliberating and rival publics.
The research also applies theories of the public sphere to the theories of art and participation associated with socially-engaged art practice - theories that articulate art in relation to its publics. While socially-engaged artists have produced new modes of art practice that have shifted arts ontology, the research points to how Third Way cultural policy was quick to seize upon socially-engaged art for its own agenda.
Public sphere theory informed the strategies and tactics of the Freee art collective (Dave Beech, Andy Hewitt, Mel Jordan) in the production of publicly-funded artworks. The artworks were a means to test the hypothesis and to find evidence by intervening in Third Way cultural policy with alternative ideas. Freee’s public spherian art proposes new modes of participative art to counter Third Way cultural policy - a ‘counter-public art’
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