Some Experiments on the Flow of Miscible Fluids of Unequal Density Through Porous Media

1963 ◽  
Vol 3 (04) ◽  
pp. 277-280 ◽  
Author(s):  
F.E. Crane ◽  
H.A. Kendall ◽  
G.H.F. Gardner

Introduction Craig, et al investigated the effect of gravity on frontal displacements for circumstances in which the gravity forces were significant. Blackwell, et al, dealt with the other extreme in which gravity forces were negligible. The considerable difference between their results is illustrated in Fig. 1 where the breakthrough recoveries are plotted against the mobility ratio. The experiments described in the present paper were conducted to examine how the transition from the one extreme case to the other occurs when the gravity forces are gradually reduced.The transition is well illustrated by the production history after breakthrough. Fig. 2 shows how the number of pore volumes which must be injected at a constant rate to displace 98 per cent of the original fluid depends on the gravity force. For each mobility ratio there is a transition range, and a very significant change in the number of pore volumes occurs when this range is transversed. This range of the gravity force is physically linked withtheformationofviscousfingers.A single finger is predominant for larger gravity forces; a multiplicity of fingers is formed for smaller gravity forces. Improved recovery and the occurrence of multiple fingers is concomitant with a large increase in the amount by which the fluids are mixed within the porous medium.The transition range depends on all the dimensionless groups which characterize the problem; but this dependence has not been exhaustively studied as yet and only fragmentary results are discussed in this paper. SPEJ P. 277^

1976 ◽  
Vol 31 (8) ◽  
pp. 981-986 ◽  
Author(s):  
F. Willig ◽  
G. Scherer

Abstract The efficiency of hole injection from electrolytic contacts into organic insulator crystals is con-trolled by hole generation and hole destruction at the crystal surface through oxidized and reduced redox ions respectively and by hole escape into the crystal bulk which competes with hole destruction. By increasing the concentration of reduced redox ions from virtually zero in a suitable system the transition has been studied from the one extreme case where all the generated holes contribute to the injection current to the other extreme case where the majority of the generated holes recombines with reduced redox ions before they can escape into the crystal bulk. From the experiments one can deduce that the generated hole spends less than 10-10 s within the reaction distance of its reduced parent redox ion, at external field strengths ≧ 104 V/cm, but returns to the crystal surface during a much longer time, e.g. during about 10-8 s at an external field strength of 105 V/cm, before it can escape finally into the crystal bulk.


1984 ◽  
Vol 98 (1) ◽  
pp. 97-107 ◽  
Author(s):  
R Kamiya ◽  
G B Witman

When detergent-extracted, demembranated cell models of Chlamydomonas were resuspended in reactivation solutions containing less than 10(-8) M Ca++, many models initially swam in helical paths similar to those of intact cells; others swam in circles against the surface of the slide or coverslip. With increasing time after reactivation, fewer models swam in helices and more swam in circles. This transition from helical to circular swimming was the result of a progressive inactivation of one of the axonemes; in the extreme case, one axoneme was completely inactive whereas the other beat with a normal waveform. At these low Ca++ concentrations, the inactivated axoneme was the trans-axoneme (the one farthest from the eyespot) in 70-100% of the models. At 10(-7) or 10(-6) M Ca++, cell models also proceeded from helical to circular swimming as a result of inactivation of one of the axonemes; however, under these conditions the cis-axoneme was usually the one that was inactivated. At 10(-8) M Ca++, most cells continued helical swimming, indicating that both axonemes were remaining relatively active. The progressive, Ca++-dependent inactivation of the trans- or cis-axoneme was reversed by switching the cell models to higher or lower Ca++ concentrations, respectively. A similar reversible, selective inactivation of the trans-flagellum occurred in intact cells swimming in medium containing 0.5 mM EGTA and no added Ca++. The results show that there are functional differences between the two axonemes of Chlamydomonas. The differential responses of the axonemes to submicromolar concentrations of Ca++ may form the basis for phototactic turning.


1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


2005 ◽  
Vol 44 (03) ◽  
pp. 107-117
Author(s):  
R. G. Meyer ◽  
W. Herr ◽  
A. Helisch ◽  
P. Bartenstein ◽  
I. Buchmann

SummaryThe prognosis of patients with acute myeloid leukaemia (AML) has improved considerably by introduction of aggressive consolidation chemotherapy and haematopoietic stem cell transplantation (SCT). Nevertheless, only 20-30% of patients with AML achieve long-term diseasefree survival after SCT. The most common cause of treatment failure is relapse. Additionally, mortality rates are significantly increased by therapy-related causes such as toxicity of chemotherapy and complications of SCT. Including radioimmunotherapies in the treatment of AML and myelodyplastic syndrome (MDS) allows for the achievement of a pronounced antileukaemic effect for the reduction of relapse rates on the one hand. On the other hand, no increase of acute toxicity and later complications should be induced. These effects are important for the primary reduction of tumour cells as well as for the myeloablative conditioning before SCT.This paper provides a systematic and critical review of the currently used radionuclides and immunoconjugates for the treatment of AML and MDS and summarizes the literature on primary tumour cell reductive radioimmunotherapies on the one hand and conditioning radioimmunotherapies before SCT on the other hand.


2017 ◽  
Vol 47 (188) ◽  
pp. 487-494
Author(s):  
Daniel Mullis

In recent years, political and social conditions have changed dramatically. Many analyses help to capture these dynamics. However, they produce political pessimism: on the one hand there is the image of regression and on the other, a direct link is made between socio-economic decline and the rise of the far-right. To counter these aspects, this article argues that current political events are to be understood less as ‘regression’ but rather as a moment of movement and the return of deep political struggles. Referring to Jacques Ranciere’s political thought, the current conditions can be captured as the ‘end of post-democracy’. This approach changes the perspective on current social dynamics in a productive way. It allows for an emphasis on movement and the recognition of the windows of opportunity for emancipatory struggles.


1996 ◽  
pp. 13-23
Author(s):  
Mykhailo Babiy

Political ideological pluralism, religious diversity are characteristic features of modern Ukrainian society. On the one hand, multiculturalism, socio-political, religious differentiation of the latter appear as important characteristics of its democracy, as a practical expression of freedom, on the other - as a factor that led to the deconsocialization of society, gave rise to "nodal points" of tension, confrontational processes, in particular, in political and religious spheres.


2003 ◽  
pp. 15-26
Author(s):  
P. Wynarczyk
Keyword(s):  
The Core ◽  

Two aspects of Schumpeter' legacy are analyzed in the article. On the one hand, he can be viewed as the custodian of the neoclassical harvest supplementing to its stock of inherited knowledge. On the other hand, the innovative character of his works is emphasized that allows to consider him a proponent of hetherodoxy. It is stressed that Schumpeter's revolutionary challenge can lead to radical changes in modern economics.


2018 ◽  
pp. 49-68 ◽  
Author(s):  
M. E. Mamonov

Our analysis documents that the existence of hidden “holes” in the capital of not yet failed banks - while creating intertemporal pressure on the actual level of capital - leads to changing of maturity of loans supplied rather than to contracting of their volume. Long-term loans decrease, whereas short-term loans rise - and, what is most remarkably, by approximately the same amounts. Standardly, the higher the maturity of loans the higher the credit risk and, thus, the more loan loss reserves (LLP) banks are forced to create, increasing the pressure on capital. Banks that already hide “holes” in the capital, but have not yet faced with license withdrawal, must possess strong incentives to shorten the maturity of supplied loans. On the one hand, it raises the turnovers of LLP and facilitates the flexibility of capital management; on the other hand, it allows increasing the speed of shifting of attracted deposits to loans to related parties in domestic or foreign jurisdictions. This enlarges the potential size of ex post revealed “hole” in the capital and, therefore, allows us to assume that not every loan might be viewed as a good for the economy: excessive short-term and insufficient long-term loans can produce the source for future losses.


2009 ◽  
pp. 18-31
Author(s):  
G. Rapoport ◽  
A. Guerts

In the article the global crisis of 2008-2009 is considered as superposition of a few regional crises that occurred simultaneously but for different reasons. However, they have something in common: developed countries tend to maintain a strong level of social security without increasing the real production output. On the one hand, this policy has resulted in trade deficit and partial destruction of market mechanisms. On the other hand, it has clashed with the desire of several oil and gas exporting countries to receive an exclusive price for their energy resources.


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