931 resultados para Taylor vortex
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Decision of the Court of King's Bench providing that, regardless of the provisions of the Statute of Anne 1710 (uk_1710), an author enjoyed the exclusive right of publishing his work in perpetuity.
Lord Mansfield, leading a majority decision of the court, provides a robust and influential justification as to the existence of an author's rights in literary property at common law. Yates, J., focussing upon the potential detriment to the public that would flow from the existence of a perpetual right, provides the dissenting opinion. The commentary explores the background to the litigation, in particular the nature of the threat which the Scottish reprint industry posed to the London book trade, relevant case-law leading up to the decision, as well as the substance of the judicial opinions.
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The comments of Charles Kegan Paul, the Victorian publisher who was involved in publishing the novels of the nineteenth-century British-Indian author Philip Meadows Taylor as single volume reprints in the 1880s, are illuminating. They are indicative of the publisher's position with regard to publishing - that there was often no correlation between commercial success and the artistic merit of a work. According to Kegan Paul, a substandard or mediocre text would be commercially successful as long it met a perceived want on the part of the public. In effect, the ruminations of the publisher suggests that a firm desirous of acquiring commercial success for a work should be an astute judge of the pre-existing wants of consumers within the market. Yet Theodor Adorno, writing in the mid-twentieth century, offers an entirely distinctive perspective to Kegan Paul's observations, arguing that there is nothing foreordained about consumer demand for certain cultural tropes or productions. They in fact are driven by an industry that preempts and conditions the possible reactions of the consumer. Both Kegan Paul's and Adorno's insights are illuminating when it comes to addressing the key issues explored in this essay. Kegan Paul's comments allude to the ways in which the publisher's promotion of Philip Meadows Taylor's fictional depictions of India and its peoples were to a large extent driven in the mid- to late-nineteenth century by their expectations of what metropolitan readers desired at any given time, whereas Adorno's insights reveal the ways in which British-Indian narratives and the public identity of their authors were not assured in advance, but were, to a large extent, engineered by the publishing industry and the literary marketplace.
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This paper presents a three dimensional, thermos-mechanical modelling approach to the cooling and solidification phases associated with the shape casting of metals ei. Die, sand and investment casting. Novel vortex-based Finite Volume (FV) methods are described and employed with regard to the small strain, non-linear Computational Solid Mechanics (CSM) capabilities required to model shape casting. The CSM capabilities include the non-linear material phenomena of creep and thermo-elasto-visco-plasticity at high temperatures and thermo-elasto-visco-plasticity at low temperatures and also multi body deformable contact with which can occur between the metal casting of the mould. The vortex-based FV methods, which can be readily applied to unstructured meshes, are included within a comprehensive FV modelling framework, PHYSICA. The additional heat transfer, by conduction and convection, filling, porosity and solidification algorithms existing within PHYSICA for the complete modelling of all shape casting process employ cell-centred FV methods. The termo-mechanical coupling is performed in a staggered incremental fashion, which addresses the possible gap formation between the component and the mould, and is ultimately validated against a variety of shape casting benchmarks.
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Abstract not available
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The purification of B-phycoerythrin from a concentrated extract of disrupted Porphyridium cruentum cells was carried out using a new vortex flow reactor design for protein purification. The reactor behaved as an expanded bed in the laminar vortices flow regime where the Streamline DEAE resin was expanded by the axial flow and stabilized by the vortex flow. After the broth culture was centrifuged and resuspended in the adsorption buffer, the concentrated extract of disrupted cells was directly loaded into the vortex flow reactor. The purification of B-phycoerythrin was carried out in two steps: adsorption in the expanded bed and elution from the settled bed. 142.0 mg of B-phycoerythrin was eluted representing a total recovery yield of 86.6%. Prior to B-phycoerythrin purification, the protein adsorption of the vortex flow reactor was characterized through hydrodynamic studies and a dynamic capacity measurement using a standard protein.
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Sammelrezension von: 1. Edward W. Taylor / Patricia Cranton, and Associates (Hrsg.): The Handbook of Transformative Learning, Theory, Research, and Practice, San Francisco, CA: Jossey-Bass 2012 (598 S.; ISBN 978-1-111-21891-4) 2. Jack Mezirow / Edward W. Taylor, and Associates (Hrsg.): Transformative Learning in Practice, Insights from Community, Workplace, and Higher Education, San Francisco, CA: Jossey-Bass 2009 (303 S.; ISBN 978-0-470-25790-6)
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The performance of supersonic engine inlets and external aerodynamic surfaces can be critically affected by shock wave / boundary layer interactions (SBLIs), whose severe adverse pressure gradients can cause boundary layer separation. Currently such problems are avoided primarily through the use of boundary layer bleed/suction which can be a source of significant performance degradation. This study investigates a novel type of flow control device called micro-vortex generators (µVGs) which may offer similar control benefits without the bleed penalties. µVGs have the ability to alter the near-wall structure of compressible turbulent boundary layers to provide increased mixing of high speed fluid which improves the boundary layer health when subjected to flow disturbance. Due to their small size,µVGs are embedded in the boundary layer which provide reduced drag compared to the traditional vortex generators while they are cost-effective, physically robust and do not require a power source. To examine the potential of µVGs, a detailed experimental and computational study of micro-ramps in a supersonic boundary layer at Mach 3 subjected to an oblique shock was undertaken. The experiments employed a flat plate boundary layer with an impinging oblique shock with downstream total pressure measurements. The moderate Reynolds number of 3,800 based on displacement thickness allowed the computations to use Large Eddy Simulations without the subgrid stress model (LES-nSGS). The LES predictions indicated that the shock changes the structure of the turbulent eddies and the primary vortices generated from the micro-ramp. Furthermore, they generally reproduced the experimentally obtained mean velocity profiles, unlike similarly-resolved RANS computations. The experiments and the LES results indicate that the micro-ramps, whose height is h≈0.5δ, can significantly reduce boundary layer thickness and improve downstream boundary layer health as measured by the incompressible shape factor, H. Regions directly behind the ramp centerline tended to have increased boundary layer thickness indicating the significant three-dimensionality of the flow field. Compared to baseline sizes, smaller micro-ramps yielded improved total pressure recovery. Moving the smaller ramps closer to the shock interaction also reduced the displacement thickness and the separated area. This effect is attributed to decreased wave drag and the closer proximity of the vortex pairs to the wall. In the second part of the study, various types of µVGs are investigated including micro-ramps and micro-vanes. The results showed that vortices generated from µVGs can partially eliminate shock induced flow separation and can continue to entrain high momentum flux for boundary layer recovery downstream. The micro-ramps resulted in thinner downstream displacement thickness in comparison to the micro-vanes. However, the strength of the streamwise vorticity for the micro-ramps decayed faster due to dissipation especially after the shock interaction. In addition, the close spanwise distance between each vortex for the ramp geometry causes the vortex cores to move upwards from the wall due to induced upwash effects. Micro-vanes, on the other hand, yielded an increased spanwise spacing of the streamwise vortices at the point of formation. This resulted in streamwise vortices staying closer to the wall with less circulation decay, and the reduction in overall flow separation is attributed to these effects. Two hybrid concepts, named “thick-vane” and “split-ramp”, were also studied where the former is a vane with side supports and the latter has a uniform spacing along the centerline of the baseline ramp. These geometries behaved similar to the micro-vanes in terms of the streamwise vorticity and the ability to reduce flow separation, but are more physically robust than the thin vanes. Next, Mach number effect on flow past the micro-ramps (h~0.5δ) are examined in a supersonic boundary layer at M=1.4, 2.2 and 3.0, but with no shock waves present. The LES results indicate that micro-ramps have a greater impact at lower Mach number near the device but its influence decays faster than that for the higher Mach number cases. This may be due to the additional dissipation caused by the primary vortices with smaller effective diameter at the lower Mach number such that their coherency is easily lost causing the streamwise vorticity and the turbulent kinetic energy to decay quickly. The normal distance between the vortex core and the wall had similar growth indicating weak correlation with the Mach number; however, the spanwise distance between the two counter-rotating cores further increases with lower Mach number. Finally, various µVGs which include micro-ramp, split-ramp and a new hybrid concept “ramped-vane” are investigated under normal shock conditions at Mach number of 1.3. In particular, the ramped-vane was studied extensively by varying its size, interior spacing of the device and streamwise position respect to the shock. The ramped-vane provided increased vorticity compared to the micro-ramp and the split-ramp. This significantly reduced the separation length downstream of the device centerline where a larger ramped-vane with increased trailing edge gap yielded a fully attached flow at the centerline of separation region. The results from coarse-resolution LES studies show that the larger ramped-vane provided the most reductions in the turbulent kinetic energy and pressure fluctuation compared to other devices downstream of the shock. Additional benefits include negligible drag while the reductions in displacement thickness and shape factor were seen compared to other devices. Increased wall shear stress and pressure recovery were found with the larger ramped-vane in the baseline resolution LES studies which also gave decreased amplitudes of the pressure fluctuations downstream of the shock.
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"Principal authorities": vol.1. p.[xiii]-xiv.
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Practical application of flow boiling to ground- and space-based thermal management systems hinges on the ability to predict the system’s heat removal capabilities under expected operating conditions. Research in this field has shown that the heat transfer coefficient within two-phase heat exchangers can be largely dependent on the experienced flow regime. This finding has inspired an effort to develop mechanistic heat transfer models for each flow pattern which are likely to outperform traditional empirical correlations. As a contribution to the effort, this work aimed to identify the heat transfer mechanisms for the slug flow regime through analysis of individual Taylor bubbles. An experimental apparatus was developed to inject single vapor Taylor bubbles into co-currently flowing liquid HFE 7100. The heat transfer was measured as the bubble rose through a 6 mm inner diameter heated tube using an infrared thermography technique. High-speed flow visualization was obtained and the bubble film thickness measured in an adiabatic section. Experiments were conducted at various liquid mass fluxes (43-200 kg/m2s) and gravity levels (0.01g-1.8g) to characterize the effect of bubble drift velocity on the heat transfer mechanisms. Variable gravity testing was conducted during a NASA parabolic flight campaign. Results from the experiments showed that the drift velocity strongly affects the hydrodynamics and heat transfer of single elongated bubbles. At low gravity levels, bubbles exhibited shapes characteristic of capillary flows and the heat transfer enhancement due to the bubble was dominated by conduction through the thin film. At moderate to high gravity, traditional Taylor bubbles provided small values of enhancement within the film, but large peaks in the wake heat transfer occurred due to turbulent vortices induced by the film plunging into the trailing liquid slug. Characteristics of the wake heat transfer profiles were analyzed and related to the predicted velocity field. Results were compared and shown to agree with numerical simulations of colleagues from EPFL, Switzerland. In addition, a preliminary study was completed on the effect of a Taylor bubble passing through nucleate flow boiling, showing that the thinning thermal boundary layer within the film suppressed nucleation, thereby decreasing the heat transfer coefficient.