23,150 research outputs found
Phosphonium chloride for thermal storage
Development of systems for storage of thermal energy is discussed. Application of phosphonium chloride for heat storage through reversible dissociation is described. Chemical, physical, and thermodynamic properties of phosphonium chloride are analyzed and dangers in using phosphonium chloride are explained
Regenerable metallic oxide systems for removal of carbon dioxide: A concept
Design concepts for portable canisters for removal of carbon dioxide are described. One is screen pack configuration consisting of brazed rectangular canister with four metal oxide packs inserted. Other is radial flow canister with perforated central tube. Methods of production and operating principles are presented
The Feynman-Wilson gas and the Lund model
We derive a partition function for the Lund fragmentation model and compare
it with that of a classical gas. For a fixed rapidity ``volume'' this partition
function corresponds to a multiplicity distribution which is very close to a
binomial distribution. We compare our results with the multiplicity
distributions obtained from the JETSET Monte Carlo for several scenarios.
Firstly, for the fragmentation vertices of the Lund string. Secondly, for the
final state particles both with and without decays.Comment: Latex, 21+1 pages, 11 figure
Advanced extravehicular protective system Interim report, 1 Jul. 1970 - 31 May 1971
Regenerable portable life support systems concepts for EVA use in 1980 and technology assessmen
An FPGA Implementation of Kak's Instantaneously-Trained, Fast-Classification Neural Networks
Motivated by a biologically plausible short-memory sketchpad, Kak's Fast Classification (FC) neural networks are instantaneously trained by using a prescriptive training scheme. Both weights and the topology for an FC network are specified with only two presentations of the training samples. Compared with iterative learning algorithms such as Backpropagation (which may require many thousands of presentations of the training data), the training of FC networks is extremely fast and learning convergence is always guaranteed. Thus FC networks are suitable for applications where real-time classification and adaptive filtering are needed. In this paper we show that FC networks are "hardware friendly" for implementation on FPGAs. Their unique prescriptive learning scheme can be integrated with the hardware design of the FC network through parameterization and compile-time constant folding
Solid amine compounds as sorbents for carbon dioxide: A concept
Solid amine compounds were examined as possible absorbents for removal of carbon dioxide in life support systems of type which may be employed in high altitude aircraft, spacecraft, or submarines. Many solid amine compounds release absorbed carbon dioxide when heated in vacuum, therefore, when properly packaged spent amine compounds can be readily regenerated and put back into service
Synthesizing Program Input Grammars
We present an algorithm for synthesizing a context-free grammar encoding the
language of valid program inputs from a set of input examples and blackbox
access to the program. Our algorithm addresses shortcomings of existing grammar
inference algorithms, which both severely overgeneralize and are prohibitively
slow. Our implementation, GLADE, leverages the grammar synthesized by our
algorithm to fuzz test programs with structured inputs. We show that GLADE
substantially increases the incremental coverage on valid inputs compared to
two baseline fuzzers
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Visualising gas heating from an RF plasma loudspeaker
In an electro-acoustic transduction mechanism, an ac modulation (here in the audio frequency range) of the electric field in an atmospheric pressure air plasma gives rise to a rapid increase in the gas temperature and dimensions of the gas volume. As in natural lightning, the rapid expansion in the ionised column though the air produces external pressure variations at the modulation frequency.
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Spatial and temporal measurement of the gas temperature can identify the nature of the thermal expansion and provide a direct approach to understanding its relationship to the sound pressure wave that is generated. However, the established method through spectroscopic measurement of rotational line emission from nitrogen molecules is limited to the main current channel where relaxation and subsequent optical emission of the excited nitrogen molecules occurs. The wider picture is revealed through the use of the Schlieren method where the refractive index gradients caused by gas heating in the plasma are imaged
Size-scaling limits of impulsive elastic energy release from a resilin-like elastomer
Elastically-driven motion has been used as a strategy to achieve high speeds
in small organisms and engineered micro-robotic devices. We examine the
size-scaling relations determining the limit of elastic energy release from
elastomer bands with mechanical properties similar to the biological protein
resilin. The maximum center-of-mass velocity of the elastomer bands was found
to be size-scale independent, while smaller bands demonstrated larger
accelerations and shorter durations of elastic energy release. Scaling
relationships determined from these measurements are consistent with the
performance of small organisms which utilize elastic elements to power motion.
Engineered devices found in the literature do not follow the same size-scaling
relationships, which suggests an opportunity for improved design of engineered
devices.Comment: 9 pages, 4 figure
Radio-wave propagation in the non-Gaussian interstellar medium
Radio waves propagating from distant pulsars in the interstellar medium
(ISM), are refracted by electron density inhomogeneities, so that the intensity
of observed pulses fluctuates with time. The theory relating the observed pulse
time-shapes to the electron-density correlation function has developed for 30
years, however, two puzzles have remained. First, observational scaling of
pulse broadening with the pulsar distance is anomalously strong; it is
consistent with the standard model only when non-uniform statistics of electron
fluctuations along the line of sight are assumed. Second, the observed pulse
shapes are consistent with the standard model only when the scattering material
is concentrated in a narrow slab between the pulsar and the Earth.
We propose that both paradoxes are resolved at once if one assumes stationary
and uniform, but non-Gaussian statistics of the electron-density distribution.
Such statistics must be of Levy type, and the propagating ray should exhibit a
Levy flight. We propose that a natural realization of such statistics may be
provided by the interstellar medium with random electron-density
discontinuities. We develop a theory of wave propagation in such a non-Gaussian
random medium, and demonstrate its good agreement with observations. The
qualitative introduction of the approach and the resolution of the
anomalous-scaling paradox was presented earlier in [PRL 91, 131101 (2003); ApJ
584, 791 (2003)].Comment: 27 pages, changes to match published versio
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