18,354 research outputs found
Synthesis of a new class of highly fluorinated aliphatic diisocyanates
Synthesis is basis for preparation of polyurethanes that are compatible with liquid oxygen. The two step process preparation from fluorocarbon diacid fluorides is explained in text
The Refined Elliptic Genus and Coulomb Gas Formulations of Superconformal Coset Models
We describe, in some detail, a number of different Coulomb gas formulations
of superconformal coset models. We also give the mappings between these
formulations. The ultimate purpose of this is to show how the Landau-Ginzburg
structure of these models can be used to extract the -generators, and to
show how the computation of the elliptic genus can be refined so as to extract
very detailed information about the characters of component parts of the model.Comment: 40 pages in harvmac, no figure
MLS vertical guidance and navigation for a STOL airplane landing on an elevated STOLport
In contrast to CTOL landing operations, STOL airplanes landing on short STOLport runways typically begin the flare maneuver before reaching the runway surface. Vertical guidance procedures were developed to allow an autoland flight control system for a STOL airplane to use Microwave Landing System (MLS) signals as altitude and sink rate references for flare initiation, with a transition to radar altimeter after the airplane is over the runway. The implementation has minimum impact on the control system and landing performance. Data are presented which show validation of the concepts in a simulator
A Challenge to All: Raising the Participation and Success of Women and Minorities in Mathematics, Science, and Technlogy
This issue of our journal is the product of a Virginia Mathematics and Science Coalition (VMSC) conference titled, Programs That Work and held in March, 2000 on the issues of raising both the levels of success and the levels of participation of women and minorities in mathematics, science, and technology. Traditionally, these two groups have had low rates of participation in these subjects, and we believe this situation can and must be changed. The conference was to Coalition\u27s first direct assault on the problem
Opponents and supporters of water policy change in the Netherlands and Hungary
This paper looks at the role of individuals and the strategies that they use to bring about or oppose major policy change. Current analysis of the role that individuals or small collectives play in periods of major policy change has focussed on strategies that reinforce change and on the supporters of change. This paper adds the perspective of opponents, and asks whether they use similar strategies as those identified for supporters. Five strategies are explored: developing new ideas, building coalitions to sell ideas, using windows of opportunity, playing multiple venues and orchestrating networks. Using empirical evidence from Dutch and Hungarian water policy change, we discuss whether individuals pursued these strategies to support or oppose major policy change. Our analysis showed the significance of recognition of a new policy concept at an abstract level by responsible government actors, as well as their engagement with a credible regional coalition that can contextualise and advocate the concept regionally. The strategies of supporters were also used by opponents of water policy change. Opposition was inherent to policy change, and whether or not government actors sought to engage with opponents influenced the realisation of water policy change
Economic Reform and the Process of Global Integration
macroeconomics, economic reform, global integration
Investigating the BPS Spectrum of Non-Critical E_n Strings
We use the effective action of the non-critical strings to study its
BPS spectrum for . We show how to introduce mass parameters, or
Wilson lines, into the effective action, and then perform the appropriate
asymptotic expansions that yield the BPS spectrum. The result is the
character expansion of the spectrum, and is equivalent to performing the mirror
map on a Calabi-Yau with up to nine K\"ahler moduli. This enables a much more
detailed examination of the structure of the theory, and provides
extensive checks on the effective action description of the non-critical
string. We extract some universal ( independent) information concerning
the degeneracies of BPS excitations.Comment: 50 pages, harvmac (b
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