10,387 research outputs found
Grille spectrometer (grille)
The Grille spectrometer was designed and flown on Spaceklab 1 by two organizations: The Office National d'Etudes et de Recherches Aerospatiales in France and the Belgian Institute for Space Aeronomy in Belgium. Its purpose is to study, on a global scale, atmospheric parameters between 15 and 150 km altitude. The investigation uses high-resolution (better than 0.1/cm) spectroscopic observations of the earth's limb in the wavelength range characteristic of the vibrational-rotational lines of the relevant atmospheric constituents. Characteristics and proposed modifications of the grille spectrometer are described. This instrument will be part of the atmospheric science research payload flown on the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission planned for late 1990
Scheduling of material through a steel plant
This paper addresses the optimal scheduling of material in a steel plant. The genetic algorithm is adapted to handle various constraints in the processing mills
Diversity of knot solitons in liquid crystals manifested by linking of preimages in torons and hopfions
Topological solitons are knots in continuous physical fields classified by
non-zero Hopf index values. Despite arising in theories that span many branches
of physics, from elementary particles to condensed matter and cosmology, they
remain experimentally elusive and poorly understood. We introduce a method of
experimental and numerical analysis of such localized structures in liquid
crystals that, similar to the mathematical Hopf maps, relates all points of the
medium's order parameter space to their closed-loop preimages within the
three-dimensional solitons. We uncover a surprisingly large diversity of
naturally occurring and laser-generated topologically nontrivial solitons with
differently knotted nematic fields, which previously have not been realized in
theories and experiments alike. We discuss the implications of the liquid
crystal's non-polar nature on the knot soliton topology and how the medium's
chirality, confinement and elastic anisotropy help to overcome the constrains
of the Hobart-Derrick theorem, yielding static three-dimensional solitons
without or with additional defects. Our findings will establish chiral nematics
as a model system for experimental exploration of topological solitons and may
impinge on understanding of such nonsingular field configurations in other
branches of physics, as well as may lead to technological application
06-07 “The Economics of Inaction on Climate Change: A Sensitivity Analysis”
Economic models of climate change often take the problem seriously, but paradoxically conclude that the optimal policy is to do almost nothing about it. We explore this paradox as seen in the widely used DICE model. Three aspects of that model, involving the discount rate, the assumed benefits of moderate warming, and the treatment of the latest climate science, are sufficient to explain the timidity of the model's optimal policy recommendation. With modifications to those three points, DICE shows that the optimal policy is a much higher and rapidly rising marginal carbon price; that higher carbon price has a greater effect on physical measures of climate impacts. Our modifications exhibit nonlinear interactions; at least at low discount rates, there is synergy between individual changes to the model. At low discount rates, the inherent uncertainty about future damages looms larger in the analysis, rendering long-run economic modeling less useful. Our analysis highlights the sensitivity of the model to three debatable assumptions; it does not, and could not, lead to a more reliably “optimal” cost of carbon. Cost-effectiveness analysis, focusing on the generally shorter-term cost side of the problem, reduces the economic paradoxes of the long run, and may make a greater contribution than economic optimization modeling.
The thermodynamic properties of the wustite phase are studied
Study of the precise location of the wustite phase boundaries and the dependence of the partial pressure of oxygen on the temperature and composition of the solid phase was made. From the pressure of oxygen, the temperature and the composition thermodynamic quantities can be determined
Contour spectrograms for POGO analysis
Contour spectrograms for POGO analysis in Saturn S-2 and S-4b stage
The Carpenter-Bees of the United States of the Genus Xylocopa
This paper forms the major part of a thesis for the degree of master of science at the Massachusetts Agricultural College, and it has been prepared under the supervision of Dr. H. T. Fernald. It is an endeavor to make more easy the identification of the bees of this genus
Letter from J. H. Ackerman
Letter concerning programs of domestic science and art in Oregon
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