4,278 research outputs found
Biodegradable Polylactic Acid (PLA) Microstructures for Scaffold Applications
In this research, we present a simple and cost effective soft lithographic
process to fabricate PLA scaffolds for tissue engineering. In which, the
negative photoresist JSR THB-120N was spun on a glass subtract followed by
conventional UV lithographic processes to fabricate the master to cast the PDMS
elastomeric mold. A thin poly(vinyl alcohol) (PVA) layer was used as a mode
release such that the PLA scaffold can be easily peeled off. The PLA precursor
solution was then cast onto the PDMS mold to form the PLA microstructures.
After evaporating the solvent, the PLA microstructures can be easily peeled off
from the PDMS mold. Experimental results show that the desired microvessels
scaffold can be successfully transferred to the biodegradable polymer PLA.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/EDA-Publishing
Operation of LANDSAT automatic tracking system
There are no author-identified significant results in this report
Topological optimisation of rod-stirring devices
There are many industrial situations where rods are used to stir a fluid, or
where rods repeatedly stretch a material such as bread dough or taffy. The goal
in these applications is to stretch either material lines (in a fluid) or the
material itself (for dough or taffy) as rapidly as possible. The growth rate of
material lines is conveniently given by the topological entropy of the rod
motion. We discuss the problem of optimising such rod devices from a
topological viewpoint. We express rod motions in terms of generators of the
braid group, and assign a cost based on the minimum number of generators needed
to write the braid. We show that for one cost function -- the topological
entropy per generator -- the optimal growth rate is the logarithm of the golden
ratio. For a more realistic cost function,involving the topological entropy per
operation where rods are allowed to move together, the optimal growth rate is
the logarithm of the silver ratio, . We show how to construct
devices that realise this optimal growth, which we call silver mixers.Comment: 22 pages, 53 figures. PDFLaTeX with RevTex4 macros
- …