Search results for "liquid"
showing 10 items of 4351 documents
Shapes and oscillations of raindrops with reduced surface tensions: Measurements at the Mainz vertical wind tunnel
2013
Abstract Important characteristics of raindrops pertinent to fields in atmospheric sciences such as weather radar or pollution scavenging are drop shape, oscillation frequency and amplitude, as well as the internal circulation. Atmospheric raindrops are never pure water drops but contain additional components like aerosol particles and dissolved species. Surface active substances, when present, reduce the surface tension of raindrops and, thus, increase the drop deformation which in turn affects breakup and coalescence, pollutant scavenging, and, finally, the formation of precipitation. Experiments were performed at the Mainz vertical wind tunnel with raindrops freely suspended at their ter…
Bimodal drop size distributions during the early stages of shear induced coalescence
2005
Drop sizes and drop size distributions were determined by means of an optical shear cell in combination with an optical microscope for the systems polyisobutylene/poly(dimethylsiloxane) (I) and poly(dimethyl-co-methylphenylsiloxane)/poly(dimethylsiloxane) (II) at low concentrations of the suspended phases and at different constant shear rates ranging from 10 to 0.5 s-1 . After pre-shearing the two-phase mixtures (I: 50 s-1; II: 100 s-1) for the purpose of producing small drop radii, the shear rate was abruptly reduced to the preselected value and coalescence was studied as a function of time. In all cases one approaches dead end drop radii, i.e. breakup is absent. The drop size distribution…
On the Role of Drop Break Up for Coalescence Processes and Morphology Development in Polymer Blends under Shear
2005
Drop sizes and drop-size distributions were determined as a function of time at constant shear rates, γ, by means of an optical shear cell in combination with an optical light microscope after preshearing the samples at high γ. The systems under investigation were PIB 3/PDMS 152 (PIB: polyisobutylene, PDMS: poly(dimethylsiloxane), numbers: average molar masses in kg/mol) and COP 26*/PDMS 48 (COP: poly(dimethyl-co-methylphenylsiloxane), asterisk: apparent molar mass); all measurements refer to 25 °C. Systems and conditions were chosen such that shear rates in the vicinity of the intersection of the coalescence and the break up curves become experimentally accessible. Under these conditi…
Wind tunnel study on the size distribution of droplets after collision induced breakup of levitating water drops
2018
Abstract Wind tunnel experiments on collisions between drop pairs of 2.5 and 0.5 mm diameter have been performed and the coalescence and breakup events have been recorded by a high-speed digital camera. From the comprehensive analysis of the captured images, the most important parameters utilized in numerical models, such as coalescence efficiency, breakup type, number of fragments and fragment size distribution after breakup were determined. The experimentally obtained parameters have been compared to parameterizations based on earlier laboratory studies of Low and List, and on direct numerical simulations. A very good agreement between experimental results and parameterizations has been f…
Cloud Particle Interactions
2010
In Chapter 10, we discussed the behavior of isolated cloud particles in sorne detai1. Now we shall consider their hydrodynamic interactions, with a view to providing a quantitative assessment of the processes of particle growth by collision and coalescence, and of collisional breakup. We shall first treat the collision problem for drops of radii less than about 500 μm which, in accordance with our previous description of drop distortion in Section 10.3.2, may be regarded as rigid spheres (at least when falling in isolation). This will be followed by a discussion of the phenomena of drop coalescence and breakup. Finally, we shall consider water drop-ice crystal and ice crystal-ice crystal in…
Growth of Cloud Drops by Collision, Coalescence and Breakup
2010
As we have already learned from our brief historical review in Chapter 1, it has long been established that the presence of ice is not always necessary for precipitation formation in clouds. In more recent times, radar observations have confirmed this early conclusion. In such cases, the flow of water up the spectrum from small droplets to rain must occur by the process of collision and coalescence of drops. This is often referred to as the collection process, and sometimes erroneously as the ‘warm rain’ process. The latter designation is somewhat inappropriate, since collection growth also occurs in clouds colder than 0°C (Braham, 1964).
Bioaccessibility and decomposition of cylindrospermopsin in vegetables matrices after the application of an in vitro digestion model.
2018
Research on the human exposure to Cylindrospermopsin (CYN) via consumption of contaminated food is of great interest for risk assessment purposes. The aim of this work is to evaluate for the first time the CYN bioaccessibility in contaminated vegetables (uncooked lettuce and spinach, and boiled spinach) after an in vitro digestion model, including the salivar, gastric and duodenal phases and, colonic fermentation under lactic acid bacteria. The results obtained showed that the digestion processes are able to diminish CYN levels, mainly in the colonic phase, especially in combination with the boiling treatment, decreasing CYN levels in a significant way. Moreover, the potential decomposition…
Some Quantitative Aspects of Stability Management Strategy in a Bank
2012
Abstract The stability of commercial bank system is the result of balanced development, which can be characterised by equilibrium and security over a longer period of time. The history of commercial bank system development indicates that reaching and sustaining this qualitative and quantitative state requires regulations and management. One of the most important parts of commercial bank management system is correctly chosen strategy in the circumstances of a changing environment. Strategy gives a possibility to look into the future of the commercial bank, forecast its goals, areas, scale and potential operational results in relation to resource sources and expenses. Nowadays a commercial ba…
Article 40. Commission d'un agent immobilier, Mandat antérieur au jugement d'ouverture, Acte de vente postérieur au jugement d'ouverture, Fait généra…
1998
International audience; (Com. 17 févr. 1998, SA Stesa c/ Gourdain ès qual. et autres)
Nullité de plein droit. La compensation provoquée est un paiement anormal prohibé en période suspecte
2008
International audience; (Com. 13 févr. 2007, pourvoi n° 05-13.526, arrêt n° 228 FS-P+B+R+I, Sté Alès béton c/ André ès-qual., Juris-Data, n° 2007-037368 ; D. 2007. AJ. 583, obs. A. Lienhard ; JCP 2007. I. 153, n° 6, obs. M. Cabrillac ; Gaz. Pal. 13-14 avr. 2007. 40, note Ph. Roussel Galle)