David Leal

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The cross-stream migration of a deformable drop in a unidirectional shear flow of a second-order fluid is considered. Expressions for the particle velocity due to the separate effects of deformation and viscoelastic rheology are obtained. The direction and magnitude of migration are calculated for the particular cases of Poiseuille flow and simple shear(More)
Ontologies reflect our view of what exists and developing ontologies for a given domain requires a common context. This context can be characterized explicitly by means of an upper ontology. Upper ontologies define top-level concepts such as physical objects, activities, mereological and topological relations from which more specific classes and relations(More)
SUMMARY The Web is an information resource with unlimited potential. However, this potential is not yet fully used since it is difficult for machines to process and integrate the meaning of the information stored on the Web. Recently the Internet community has begun to explore the potential of associating web content with explicit meaning, in order to(More)
To qualify materials for specific applications comprehensive testing is necessary, and consequently the engineering materials community has developed an extensive collection of documentary testing standards to define test conditions, specimen configurations, and post processing and reporting procedures. Unfortunately, in the absence of corresponding data(More)
The creeping motion through a circular tube of neutrally buoyant Newtonian drops which have an undeformed radius comparable to that of the tube was studied experimentally. Both a Newtonian and a viscoelastic suspending fluid were used in order to determine the influence ofviscoelasticity. The extra pressure drop owing to the presence of the suspended drops,(More)