BROWN UNIVERSITY
Joint Materials/Solid Mechanics Seminar Series
Materials and Processes Lab, General Motors Research and Development Center | |
Abstract: Most mechanical devices and manufacturing tools cannot function without a properly engineered surface. The properties of surfaces are largely determined by their composition and structure at the nano and micrometer length scales. In this presentation, I shall provide an overview of our recent work on synthesis and characterization of nanostructured materials as engineered surfaces for several automotive applications. Examples include (1) nanocomposite coatings and nanowires, (2) microscopic shape memory and superelastic effects and their tribological applications, (3) superhydrophobic surfaces, and (4) coatings for dry machining of aluminum alloys and automotive components. These examples help illustrate research opportunities in surface engineering and their novel industrial applications.
Center for Fluid Mechanics
And
The Fluids, Thermal and Chemical Processes Group
Of
The Division Of Engineering
Seminar Series
Levich Institute and Department of Chemical Engineering, City College of New York | |
Abstract: Suspensions, or particle-laden liquids, are quite commonly encountered. One can readily list examples from natural contexts such as blood and mud flows, along with applications such as coatings, cement, and ceramic precursors. Mechanistic understanding of suspension behavior is thus basic to a range of problems in physical science. The case of nearly hard spheres in Stokes flow has received abundant attention, and a few key results will be reviewed. This background will motivate our examination by both experiment and analysis of the much less-studied cases of 1) free surface shear flows of concentrated suspensions, and 2) inertial flows of liquid-solid suspensions at dilute to moderate concentrations. Note that these are separate topics for this discussion.
For the free-surface flow, we focus here upon coating type or "film" flows, and limit attention to suspensions of neutrally- buoyant suspensions, with particles density matched to the surrounding liquid. Our experiments and analysis of the simplest case of flow down an inclined plane illustrate that a Newtonian model of the flow is incomplete due to bulk migration of the particles, while the intense interactions between particles in this shear flow is reflected in a highly irregular surface structure. Suggestions of particle-induced instabilities arising from the experiments will be noted.
Changing topics, we note that inertial effects at the particle scale are characterized by a finite particle-scale Reynolds number, and much of what we discuss in regard to inertial effects will consider Re_{p} = O(1), again for neutrally buoyant particles. At the particle scale, numerical study shows that this level of inertia profoundly alters the basic flow patterns around isolated bodies, with similar changes to pair interaction trajectories. Proceeding up in scale, our experiments in tube flows show that such hydrodynamic interactions between particles under dilute (1-2% solids by volume) results in the formation of ``trains'' consisting of well-spaced and long-lived linear structures of up to about 50 particles flowing along the wall of the tube. At the bulk scale, addition of a small fraction of solids for which Re_{p} = O(1) results in a dramatic reduction in the tube-scale Reynolds number for the onset of intermittent turbulence -- the classic Re = 2100 transition is shifted below Re = 1000 for a few percent solids of 1/10 trhe tube diameter! Results for 0.2% up to 30% solids by volume will be presented. No explanation for the latter behavior has been developed.
************
Sponsored by:
Brown University's Division of Engineering,
Creative Arts Council,
Cogut Center for the Humanities
Brower Hatcher, artist, director Karl Aspelund, designer The Mid-Ocean Studio, Providence, RI | |
and Social Experience | |
(Corner of George and Thayer Street) |
Abstract: Art and design in a public venue is a factor in a community's self perception. It influences, with degrees of subtlety, the daily life of those who inhabit it, interact with it, or pass it by. Notions of beauty, worth, and social content evolve, producing a constantly changing perception. The dialog between artist, designer, environment and audience is not created in one instant or in one venue, but in the active experience of the work. Using examples from the work of the Mid-Ocean Studio and a historical survey, we will discuss concepts of beauty, communication, and the value of aesthetic experience in a social context. In addition, we will describe the contextual and environmental influences determining our aesthetic choices, specifically those that stem from scientific collaboration and research.
Brower Hatcher studied sculpture at St. Martins school of
Art in London with Anthony Caro, taught sculpture at Bennington
College in VT, is a Guggenheim fellow, and holds a Ph.D. from the
State University of New York.
See: www.browerhatcher.com
Karl Aspelund a graduate of the Wimbledon School of Art
in London, has been the lead designer for the Mid-Ocean Studio
since 2001. He is the author of The Design Process, to be
published by Fairchild Books in May, and teaches at URI.
See: www.karlaspelund.com
Brown Analysis Seminar
Scientific Computing Seminar
Abstract: In this talk we will discuss the simulation of a rarified gas between parallel plates. In particular, we will discuss a computational procedure for the BGK-model, which represents a simplified model for the full Boltzmann equation. We will discuss the mathematical formulation and the numerical treatment of this problem, and we will use the resulting framework to construct a reduced basis model for the rapid prediction of the volume flow rate with certified error bounds.
Brown University - Graduate School Dissertation Defense
PDE Seminar
Department of Mathematics Colloquium
Crazy Topology and Complex Dynamics | |
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