9,320 research outputs found
The Capillary Pumped Loop Flight Experiment (CAPL): A pathfinder for EOS
The CAPL shuttle flight experiment will provide microgravity verification of the prototype capillary pumped loop (CPL) thermal control system for EOS. The design of the experiment is discussed with particular emphasis on the new technology areas in ammonia two-phase reservior design and heat pipe heat exchanger development. The thermal and hydrodynamic analysis techniques and results are also presented, including pressure losses, fluid flow, and non-orbit heat rejection capability. CAPL experiment results will be presented after the flight, presently planned for 1993
Development and Verification of a Flight Stack for a High-Altitude Glider in Ada/SPARK 2014
SPARK 2014 is a modern programming language and a new state-of-the-art tool
set for development and verification of high-integrity software. In this paper,
we explore the capabilities and limitations of its latest version in the
context of building a flight stack for a high-altitude unmanned glider. Towards
that, we deliberately applied static analysis early and continuously during
implementation, to give verification the possibility to steer the software
design. In this process we have identified several limitations and pitfalls of
software design and verification in SPARK, for which we give workarounds and
protective actions to avoid them. Finally, we give design recommendations that
have proven effective for verification, and summarize our experiences with this
new language
Ultrasoft NLL Running of the Nonrelativistic O(v) QCD Quark Potential
Using the nonrelativistic effective field theory vNRQCD, we determine the
contribution to the next-to-leading logarithmic (NLL) running of the effective
quark-antiquark potential at order v (1/mk) from diagrams with one potential
and two ultrasoft loops, v being the velocity of the quarks in the c.m. frame.
The results are numerically important and complete the description of ultrasoft
next-to-next-to-leading logarithmic (NNLL) order effects in heavy quark pair
production and annihilation close to threshold.Comment: 25 pages, 7 figures, 3 tables; minor modifications, typos corrected,
references added, footnote adde
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