scholarly journals Averaging of flows with capillary hysteresis in stochastic porous media

2007 ◽  
Vol 18 (3) ◽  
pp. 389-415 ◽  
Author(s):  
BEN SCHWEIZER
Keyword(s):  
Porous Media ◽  
Evolution Equation ◽  
Physical System ◽  
Strong Solutions ◽  
Unsaturated Porous Media ◽  
Capillary Hysteresis ◽  
History Of ◽  
Wetting Process ◽  
The Relationship ◽  
Weak And Strong Solutions

Fluids in unsaturated porous media are described by the relationship between pressure (p) and saturation (u). Darcy's law and conservation of mass provides an evolution equation for u, and the capillary pressure provides a relation between p and u of the form p∈ pc(u,∂tu). The multi-valued function pc leads to hysteresis effects. We construct weak and strong solutions to the hysteresis system and homogenize the system for oscillatory stochastic coefficients. The effective equations contain a new dependent variable that encodes the history of the wetting process and provide a better description of the physical system.

The impact of biofilm-forming potential and tafi production on transport of environmental Salmonella through unsaturated porous media

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Anthony Salvucci ◽  
Wei Zhang ◽  
Veronica Morales ◽  
M. Cakmak ◽  
Anthony Hay ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Porous Media ◽  
Biofilm Formation ◽  
Microbial Pathogens ◽  
Unsaturated Porous Media ◽  
E Coli ◽  
Unsaturated Sand ◽  
Factors Influencing ◽  
The Impact ◽  
The Relationship

AbstractUnderstanding the factors influencing the transport of microbial pathogens, such as Salmonella and Escherichia coli, through porous media is critical to protecting drinking water supplies. The production of biofilms, along with individual biofilm-associated components, such as tafi, is believed to hinder transport of microorganisms through soil. This study investigated the relationship between biofilm formation and tafi production and the transport of environmental Salmonella through porous media. Thirty-two Salmonella isolates were initially assayed for their ability to form biofilms, from which a subset of these was selected to represent a range of high and low biofilm-formation potential and tafi formation capabilities. These were subsequently examined in unsaturated sand columns for transport characteristics. No obvious correlation was observed between Salmonella phenotypes and column retention. The results indicated that while transport of well-characterized laboratory E. coli strains can often be hindered by the presence of tafi and the potential to form biofilms, the presence of tafi did not retard the transport of the Salmonella strains.

A model for capillary hysteresis loops in unsaturated porous media theory

2016 ◽  
Vol 22 (9) ◽  
pp. 1876-1890
Author(s):  
Gérard Gagneux ◽  
Olivier Millet
Keyword(s):  
Porous Media ◽  
Hysteresis Loops ◽  
Approximate Solutions ◽  
Media Theory ◽  
Unsaturated Porous Media ◽  
Capillary Hysteresis ◽  
Additional Information ◽  
Continuity Equations ◽  
Porous Media Theory ◽  
Clockwise Hysteresis

In this paper, we show how very relevant mathematical works of P.I. Plotnikov, publicized by L.C. Evans and M. Portilheiro, can be used to model the effects of cyclic hysteresis phenomena for flows in unsaturated porous media. We draw particular attention to the example of a model for water–air flows, simplified for purposes of illustration. First, an unstable “spinodal” interval is artificially introduced. Then S.L. Sobolev’s method of dynamic regularization allows associating with the continuity equations additional information in the form of entropy type inequalities. The asymptotic limits of viscous approximate solutions generate effects of irreversibility and the expected clockwise hysteresis loop.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Investigating the Relationship Between Self-Esteem and Stigma Among Young Adults With History of Suicide Attempts

Crisis ◽  
2016 ◽  
Vol 37 (4) ◽  
pp. 265-270 ◽  
Author(s):  
Meshan Lehmann ◽  
Matthew R. Hilimire ◽  
Lawrence H. Yang ◽  
Bruce G. Link ◽  
Jordan E. DeVylder
Keyword(s):  
Young Adults ◽  
Suicide Attempts ◽  
Self Esteem ◽  
High Risk Population ◽  
High Functioning ◽  
People With Mental Illness ◽  
History Of ◽  
The Individual ◽  
The Impact ◽  
The Relationship

Abstract. Background: Self-esteem is a major contributor to risk for repeated suicide attempts. Prior research has shown that awareness of stigma is associated with reduced self-esteem among people with mental illness. No prior studies have examined the association between self-esteem and stereotype awareness among individuals with past suicide attempts. Aims: To understand the relationship between stereotype awareness and self-esteem among young adults who have and have not attempted suicide. Method: Computerized surveys were administered to college students (N = 637). Linear regression analyses were used to test associations between self-esteem and stereotype awareness, attempt history, and their interaction. Results: There was a significant stereotype awareness by attempt interaction (β = –.74, p = .006) in the regression analysis. The interaction was explained by a stronger negative association between stereotype awareness and self-esteem among individuals with past suicide attempts (β = –.50, p = .013) compared with those without attempts (β = –.09, p = .037). Conclusion: Stigma is associated with lower self-esteem within this high-functioning sample of young adults with histories of suicide attempts. Alleviating the impact of stigma at the individual (clinical) or community (public health) levels may improve self-esteem among this high-risk population, which could potentially influence subsequent suicide risk.

Misreading Egypt

2018 ◽  
Author(s):  
Jesse Schotter
Keyword(s):  
New Media ◽  
Narrative Form ◽  
Experimental Film ◽  
Tower Of Babel ◽  
Avant Garde ◽  
Sergei Eisenstein ◽  
History Of ◽  
The One ◽  
The Relationship ◽  
Modern Technologies

The first chapter of Hieroglyphic Modernisms exposes the complex history of Western misconceptions of Egyptian writing from antiquity to the present. Hieroglyphs bridge the gap between modern technologies and the ancient past, looking forward to the rise of new media and backward to the dispersal of languages in the mythical moment of the Tower of Babel. The contradictory ways in which hieroglyphs were interpreted in the West come to shape the differing ways that modernist writers and filmmakers understood the relationship between writing, film, and other new media. On the one hand, poets like Ezra Pound and film theorists like Vachel Lindsay and Sergei Eisenstein use the visual languages of China and of Egypt as a more primal or direct alternative to written words. But Freud, Proust, and the later Eisenstein conversely emphasize the phonetic qualities of Egyptian writing, its similarity to alphabetical scripts. The chapter concludes by arguing that even avant-garde invocations of hieroglyphics depend on narrative form through an examination of Hollis Frampton’s experimental film Zorns Lemma.

Meat without Animals: Outcast Objects and the Improvement of London

2018 ◽  
Author(s):  
Ted Geier
Keyword(s):  
Animal Rights ◽  
Legal Reform ◽  
Meat Production ◽  
History Of ◽  
Relationship Of ◽  
The Relationship

Covers the long history of the Smithfield animal market and legal reform in London. Shows the relationship of civic improvement tropes, including animal rights, to animal erasure in the form of new foodstuffs from distant meat production sites. The reduction of lives to commodities also informed public abasement of the butchers.

A Note on the Publication History of John Polidori's The Vampyre

2020 ◽  
Vol 22 (3) ◽  
pp. 330-343
Author(s):  
Fabio Camilletti
Keyword(s):  
Textual Criticism ◽  
Active Role ◽  
Publication History ◽  
History Of ◽  
The Relationship ◽  
Opening Up

It is generally assumed that The Vampyre was published against John Polidori's will. This article brings evidence to support that he played, in fact, an active role in the publication of his tale, perhaps as a response to Frankenstein. In particular, by making use of the tools of textual criticism, it demonstrates how the ‘Extract of a Letter from Geneva’ accompanying The Vampyre in The New Monthly Magazine and in volume editions could not be written without having access to Polidori's Diary. Furthermore, it hypothesizes that the composition of The Vampyre, traditionally located in Geneva in the course of summer 1816, can be postdated to 1818, opening up new possibilities for reading the tale in the context of the relationship between Polidori, Byron, and the Shelleys.

World-Ecological Satire: Peat, Brian O'Nolan, and the Irish Free State's Energy Regime

2019 ◽  
Vol 49 (1) ◽  
pp. 90-104
Author(s):  
Robert Kiely
Keyword(s):  
Cultural Production ◽  
Ecological Perspective ◽  
Energy Regime ◽  
Energy History ◽  
History Of ◽  
External Site ◽  
Ecological Relations ◽  
Nature And Society ◽  
Human Actors ◽  
The Relationship

A world-ecological perspective of cultural production refuses a dualist conception of nature and society – which imagines nature as an external site of static outputs  – and instead foregrounds the fact that human and extra-human natures are completely intertwined. This essay seeks to reinterpret the satirical writing of a canonical figure within the Irish literary tradition, Brian O'Nolan, in light of the energy history of Ireland, understood as co-produced by both human actors and biophysical nature. How does the energy imaginary of O'Nolan's work refract and mediate the Irish environment and the socio-ecological relations shaping the fuel supply-chains that power the Irish energy regime dominant under the Irish Free State? I discuss the relationship between peat as fuel and Brian O'Nolan's pseudonymous newspaper columns, and indicate how questions about energy regimes and ecology can lead us to read his Irish language novel An Béal Bocht [The Poor Mouth] (1941) in a new light. The moments I select and analyze from O'Nolan's output feature a kind of satire that exposes the folly of separating society from nature, by presenting an exaggerated form of the myth of nature as an infinite resource.

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