1,320 research outputs found
Cutting bubbles using direct numerical simulation
No full textDue to an increase in the oil price, Fischer-Tropsch synthesis, methanol synthesis and other gas-to-liquid processes become increasingly attractive. These gas-liquid-solid processes are mostly performed in bubble slurry columns [Wang et al., 2007, Yang et al., 2007]. However, the efficiency of these columns is restricted due to limited heat removal rates or limited interfacial mass-transfer rates. To improve the efficiency of these reactors, a new reactor concept is developed: a micro-structured bubble column [Jain et al. 2013, Segers et al., 2013]. In a micro-structured bubble column, a static wire mesh is introduced. This wire mesh can be used as a catalyst carrier, eliminating a filtration unit to remove the catalyst particles from the product stream. Furthermore, the wire mesh also ensures cutting of the bubbles. This will reduce the bubble size and enable a higher surface per volume ratio [Jain et al. 2013, Segers et al., 2013]. To determine the efficiency gain due to the introduction of the wire mesh, a multi-scale modelling approach is used. In this approach there are three types of models. The largest scale models, the Euler-Euler and the Euler-Lagrangian models, need closures to accurately model the interactions between the bubbles, the liquid and the mesh. These interactions can be determined using the smallest scale model: the Direct Numerical Simulations (DNS). While these DNS models are able to simulate these interactions without any a priori assumptions, they are only capable of simulating a small part of the micro-structured bubble column [Segers et al., 2013, Roghair et al., 2011]. In this work, a DNS model was developed to study the effect of a wire mesh in a micro-structured bubble column. The DNS model is a combination of the Volume Of Fluid (VOF) model of Baltussen et al. (2014) and the second order implicit Immersed Boundary (IB) method of Deen et al. (2012). The advantage of the use of the VOF model is the relatively easy treatment of break-up of bubbles and the inherent mass conservation. The used IB method enables an implicit fluid-solid coupling, Using this VOF-IB method, the effect of the simplest wire mesh, a single wire, on a single bubble is determined. Several simulations have been performed to study the effect of the alignment of the bubble with the wire and the relative size of the bubble upon break-up. An example of such a simulation is shown in figure 1
Bubbles on the cutting edge : direct numerical simulations of gas-liquid-solid three-phase flows
Full text linkBouwlogistieke innovaties weerbarstig te implementeren
No full textToelevering van bouwmaterialen aan bouwprojecten is complex en verregaande gesegregeerd. De bouwsector staat voor een kans te innoveren op het vlak van de bouwlogistiek. In het verleden is ervaring opgedaan met ‘best-practices’ die voldoende kansen bieden de noodzakelijk innovatie door te voeren. Via proeftuinen wordt in het TKI-project ‘4C in Bouwlogistiek’ gewerkt aan het implementeren van de ‘best-practices’: bouwlogistiek hubs, bouwtickets, vandaag voor morgen, opstelstrips en mobiele voorraadcontainers. Ervaring leert dat cultuurverschillen tussen bouwkundigen en logistici, en gebrek aan meten en vastleggen van gegevens de implementatie bemoeilijken. Echte innovatie gaat mogelijk komen van bedrijven die logistiek geheel anders gaan doen. Voorbeelden van concepten die voor innovatie in bouwlogistiek kunnen zorgen zijn te vinden bij: IKEA, Toyota, Zara, Uber. Ook 3Dprinting gaat de bouwlogistiek sterk beïnvloeden.Engineering, Systems and ServicesTechnology, Policy and Managemen
Modelling Gaia: towards an Actor-Network modelling framework in archaeology
No full textGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Water Resource
Análisis del isótopo de oxígeno del Entierro 2.A, Pirámide de la Luna, Teotihuacan. 29. Arqueología
No full textSpence, M.W. y Denise To, “Los restos humanos de la primera
temporada de excavaciones en la Pirámide
de la Luna”, México, Informe al INAH, 2000,
mecanoescrito.White, C.D., et al., “Oxygen isotopes and the identification of
geographical origins: the Valley of Oaxaca versus
the Valley of México”, Journal of Archaeological
Science, núm. 25, 1998, pp. 643-655.White, C.D., M.W. Spence, Fred J. Longstaffe,
E. Rattray y K.R. Law
“Un análisis del isótopo oxígeno en los entierros
del Barrio de los Comerciantes”, ponencia
para La Segunda Mesa Redonda de Teotihuacan,
septiembre 2002.Ubelaker, D., Human skeletal remains: excavation, analysis and
interpretation, Chicago, Aldine Publishing, 1978
Special Order no. 177 (2 August 1864)
Full text linkLeave of absence (2 days) granted to M.W. Boyd to bringing absentees into camphttps://egrove.olemiss.edu/ciwar_milrec/1002/thumbnail.jp
Conceptualizing and implementing an agent-based model of an irrigation system
No full textGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Water Resource
DARE-TU Project: Co-creation of Affordable and Clean Pumped Irrigation for Smallholders
No full textAccepted Author ManuscriptWater ResourcesDesign for Sustainabilit
Letter to the Editor
Full text linkLetter - A handwritten letter to the Editor of the Alberta Report written by Ruth Gorman under the pseudonym, M.W. Eagle (5 pages)WC
Discussion of “Perceptual models of uncertainty for socio-hydrological systems: a flood risk change example”<sup> <sup>*</sup> </sup>
No full textDealing with uncertainty is key in socio-hydrological analysis. As such, thinking through what uncertainties mean for whom and when is key. This discussion contribution introduces three issues related to defining uncertainties. The first issue deals with the problem of defining uncertainty as a given external reality. The second issue deals with who decides about relevant uncertainties. The third issue deals with the issue whether coupled human-hydrological systems can be seen as existing on their own. Finally, the text provides two examples of hydrological research that try to be explicit about our dealing with multiple (interpretations of) realities.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Water Resource
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