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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Chemistry of materials 6 (1994), S. 282-286 
    ISSN: 1520-5002
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1520-5827
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 4 (1992), S. 1848-1850 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experiments on impulsively started flows about sharp edges subtending angles between 150° and 175° show that the flow remains attached for a long time, in seeming contradiction to the Kutta condition. Although certain details of the flow are not understood, comparison of viscous boundary-layer and inviscid vortex growth rates indicate that this behavior may well be due to the starting flow being of an initially viscous nature.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 1351-1355 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ring vortex evolution, from the initial roll-up phase through to the final turbulent phase, was experimentally studied to see the dependence of its stirring properties on both the initial (accelerating, constant, decelerating, slow, fast) piston motion as well as on the boundary (tube/hole geometry) conditions. Stirring between fluid initially upstream and that initially downstream of the nozzle plane is done more by convective entrainment at the beginning (roll-up and contraction phases), by diffusive entrainment during the laminar and wavy phases, and by mixed entrainment and ejection during the transition to turbulence and the turbulent phase itself. During vortex roll-up, it was found that tubes eject shorter streaklines than do holes, and that there is less Re dependence for this for tubes than for holes. During the contraction phase, entrainment ends, save for minimal entrainment due to axial inflow into the ring from along the cores of Goertler-type vortices. Generally, the rate of fluid ejected is largest during the transition from the wavy to the turbulent state. As far as the stability of the vortices is concerned, rings generated at holes are less stable than those generated at tubes. During the final turbulent phase, rings not only entrain fluid but eject it periodically into the wake: Between two and four hairpin vortices are generated and laid off in the wake during each ejection. The frequency at which such ejections takes place scales as a Strouhal number that takes on values of between 2 and 4.
    Type of Medium: Electronic Resource
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  • 5
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    Unknown
    Minneapolis : Periodicals Archive Online (PAO)
    Philosophical Studies. 48:3 (1985:Nov.) 337 
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Philosophical studies 48 (1985), S. 337-351 
    ISSN: 1573-0883
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Meccanica 29 (1994), S. 351-359 
    ISSN: 1572-9648
    Keywords: Non-circular ring vortex ; Bifurcation ; Reconnection ; Vortex dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Sommario Vortici ad anello non circolari sono intrinsecamente instabili e danno luogo ad una gamma di nuovi fenomeni. In questo articolo vengono riportati gli esperimenti degli Autori e di Heertsch in cui sono generati vortici in ugelli e fori rettangolari con rapporti geometrici λ=2÷20. Sono state anche usate differenti storie del moto del pistone. Nel caso in cui si usi solo la corsa in avanti si è stati capaci di confermare il moto tipico del vortice primario senza divisione del vortice stesso. Introducendo una corsa inversa, subito dopo la corsa in avanti, persino per λ pari circa a 2 — valore in cui il vortice non si dovrebbe dividere — i vortici si potevano dividere in due, tre o quattro vortici secondari. Nei casi in cui si verificava la riconnessione, l'evoluzione del processo era molto differente rispetto alla teoria. Per λ〈3, per una data geometria dell'ugello, l'angolo di separazione è estremamente sensibile alla lunghezza della corsa, mentre per λ=5÷9 l'angolo di separazione tende a diventare indipendente dalla corsa. Questa sensibilità è ridotta per vortici generati in fori. In tutti i casi l'angolo di separazione sembra abbastanza indipendente dal numero di Reynolds. Vortici generati in corrispondenza di fori tendono ad essere meno stabili di quelli generati in ugelli. Infine, la dipendenza dall'angolo di separazione sulla lunghezza della corsa scala con l'ampiezza dell'ugello solamente per λ=5÷7.
    Notes: Abstract Non-circular ring vortices are innately unstable, giving rise to a range of new phenomena. Here we report on our and Heertsch's [1] experiments in which vortices were generated at rectangular holes and nozzles with aspect ratios 2〈λ〈20. Different piston histories were also used. For forestrokes alone we were able to confirm the typical non-splitting motion of the primary vortex. On introducing a backstroke following the forestroke even for values of λ as low as 2 — values which should not give rise to splitting vortices — vortices could be made to split into 2, 3 or 4 secondary vortices. For cases where they rejoined the process was significantly different to that predicted by theory [2]. For λ≤3 for a nozzle geometry the splitting angle is extremely sensitive to the stroke (length) so long as splitting takes place, whereas for 9〉λ〉5 the splitting angle tends to become independent of the stroke. This sensitivity on the stroke is reduced for vortices generated at a hole geometry. For all cases investigated here the splitting angle seems to be relatively insensitive to the Reynolds number. Vortices generated at hole geometries also tend to be less stable than those generated at tube geometries. Finally, the dependence of the splitting angle on the stroke length only scales with the nozzle breadth for 7〉λ〉5.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-2800
    Keywords: acquired immunodeficiency syndrome ; data collection ; epidemiologic methods ; homosexuality ; sex behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Psychology
    Notes: Abstract Effects of sex of interviewer and place of interview on the responses of 57 AIDS patients and 145 other homosexual men were studied. Data on sensitive topics were collected by five male and three female medical officers at places convenient to respondents. Male physicians recorded fellatio more frequently, but female physicians recorded younger ages of initiating homosexual activities and more frequent use of certain recreational drugs. These differences apparently were due to different patterns of sexual contact and drug use in four cities. Patients with AIDS tended to be interviewed in hospitals and doctors' offices, other men tended to be interviewed in hotel rooms, and patients tended to be different from other men. After adjustments were made for confounding, sex of interviewer and place of interview seemed to have little influence on the answers obtained.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-2967
    Keywords: carbon dioxide ; sequestration ; plume ; pH ; toxicity ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Feasibility studies suggest that the concept of capturing CO2 from fossil fuel power plants and discharging it to the deep ocean could help reduce atmospheric CO2 concentrations. However, the local reduction in seawater pH near the point of injection is a potential environmental impact. Data from the literature reporting on toxicity of reduced pH to marine organisms potentially affected by such a plume were combined into a model expressing mortality as a function of pH and exposure time. Since organisms exposed to real plumes would experience a time‐varying pH, methods to account for a variable exposure were reviewed and a new method developed based on the concept of isomortality. In part II of this paper, the method is combined with a random‐walk model describing the transport of passive organisms through a low pH plume leading to a Monte‐Carlo‐like risk assessment which is applied to several candidate CO2 injection scenarios.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-2967
    Keywords: carbon dioxide ; plume ; pH ; random walk ; diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A method to evaluate aquatic mortality given a pollutant distribution is presented and applied to several sample low pH plumes representing various ocean CO2 disposal schemes. The method is an improvement over current analysis because it integrates the mortality due to time‐varying exposure to low pH with the probabilistic experiences of passive organisms subject to turbulent lateral diffusion as they pass through the plume. For the examples presented, the plume was discretized laterally into lanes and longitudinally by time steps, and a random walk model accounting for the scale‐dependent nature of relative diffusion was used to simulate the organism pathways over one time step. From these simulations, the probability that an organism will be in a given lane, $$\dot \jmath $$ , one time step after it starts from an initial lane, $$i$$ , was determined for all combinations of $$i$$ and $$\dot \jmath $$ . These probabilities were used to find the number of organisms following each of the possible pathways, and the mortality to the organisms due to their time varying exposure to low pH was determined by using the toxicity model described in part I of this paper. The integrated method allows the impact of the plume to be described in terms of total organism mortality as well as spatial deficit of organisms.
    Type of Medium: Electronic Resource
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