22,399 research outputs found
Detection of molecular microwave transitions in the 3 mm wavelength range in comet Kohoutek (1973f)
Observations of comet Kohoutek made with a 3-mm line receiver mounted on the 11-m NRAO radio dish at Kitt Peak are presented. The detection of line transitions of hydrogen cyanide and methyl cyanide is reported and discussed along with the variability of neutral gas jets. Microwave transitions in molecules of cometary origin are also examined
Private Options to Use Public Goods Exploiting Revealed Preferences to Estimate Environmental Benefits
We develop and apply a new method for estimating the economic benefits of an environmental amenity. The method fits within the household production framework (Becker 1965), and is based upon the notion of estimating the derived demand for a privately traded option to utilize a freely-available public good. In particular, the demand for state fishing licenses is used to infer the benefits of recreational fishing. Using panel data on state fishing license sales and prices for the continental United States over a fifteen-year period, combined with data on substitute prices and demographic variables, a license demand function is estimated with instrumental variable procedures to allow for the potential endogeneity of administered prices. The econometric results lead to estimates of the benefits of a fishing license, and subsequently to the expected benefits of a recreational fishing day. In contrast with previous studies, which have utilized travel cost or hypothetical market methods, our approach provides estimates that are directly comparable across geographic areas. Further, our results suggest that the benefits of recreational fishing days are generally less than previously estimated.Private Options, Public Goods, Environmental Benefits
Conceptual design of single turbofan engine powered light aircraft
The conceptual design of a four place single turbofan engine powered light aircraft was accomplished utilizing contemporary light aircraft conventional design techniques as a means of evaluating the NASA-Ames General Aviation Synthesis Program (GASP) as a preliminary design tool. In certain areas, disagreement or exclusion were found to exist between the results of the conventional design and GASP processes. Detail discussion of these points along with the associated contemporary design methodology are presented
Plastic Flowage of Salt in Mines at Hutchinson and Lyons, Kansas
Plastic flowage in the pillars and floors of salt mines at Hutchinson and Lyons, Kansas, is indicated by buckling, spalling, and fracturing. Detailed measurements of the relative size of the pillars in newly opened rooms and crosscuts were made over a period of 11 months. These data indicate that the salt flowage is due to pressure of the overburden and is controlled by the volume of salt excavated and configuration of the excavation. Plastic flowage causes folds and fractures to develop only in the floor of the Lyons mine. The orientation of structures and rates of flowage in the base, top, and middle of pillars are governed by the direction of easiest relief of stress, which is controlled by the mining plan
Plastic Flowage of Salt in Mines at Hutchinson and Lyons, Kansas
Plastic flowage in the pillars and floors of salt mines at Hutchinson and Lyons, Kansas, is indicated by buckling, spalling, and fracturing. Detailed measurements of the relative size of the pillars in newly opened rooms and crosscuts were made over a period of 11 months. These data indicate that the salt flowage is due to pressure of the overburden and is controlled by the volume of salt excavated and configuration of the excavation. Plastic flowage causes folds and fractures to develop only in the floor of the Lyons mine. The orientation of structures and rates of flowage in the base, top, and middle of pillars are governed by the direction of easiest relief of stress, which is controlled by the mining plan
The Hudson Bay Lithospheric Experiment (HuBLE) : Insights into Precambrian Plate Tectonics and the Development of Mantle Keels
The UK component of HuBLE was supported by Natural Environment Research Council (NERC) grant NE/F007337/1, with financial and logistical support from the Geological Survey of Canada, CanadaâNunavut Geoscience Office, SEIS-UK (the seismic node of NERC), and First Nations communities of Nunavut. J. Beauchesne and J. Kendall provided invaluable assistance in the field. Discussions with M. St-Onge, T. Skulski, D. Corrigan and M. Sanborne-Barrie were helpful for interpretation of the data. D. Eaton and F. A. Darbyshire acknowledge the Natural Sciences and Engineering Research Council. Four stations on the Belcher Islands and northern Quebec were installed by the University of Western Ontario and funded through a grant to D. Eaton (UWO Academic Development Fund). I. Bastow is funded by the Leverhulme Trust. This is Natural Resources Canada Contribution 20130084 to its Geomapping for Energy and Minerals Program. This work has received funding from the European Research Council under the European Unions Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement no. 240473 âCoMITACâ.Peer reviewedPublisher PD
Some comments on the universal constant in DSR
Deformed Special Relativity is usually presented as a deformation of Special
Relativity accommodating a new universal constant, the Planck mass, while
respecting the relativity principle. In order to avoid some fundamental
problems (e.g. soccer ball problem), we argue that we should switch point of
view and consider instead the Newton constant as the universal constant.Comment: 12 pages, Proceedings of DICE2006 (Piombino, Italy
Hartree-Fock-Bogoliubov Model and Simulation of Attractive and Repulsive Bose-Einstein Condensates
We describe a model of dynamic Bose-Einstein condensates near a Feshbach
resonance that is computationally feasible under assumptions of spherical or
cylindrical symmetry. Simulations in spherical symmetry approximate the
experimentally measured time to collapse of an unstably attractive condensate
only when the molecular binding energy in the model is correct, demonstrating
that the quantum fluctuations and atom-molecule pairing included in the model
are the dominant mechanisms during collapse. Simulations of condensates with
repulsive interactions find some quantitative disagreement, suggesting that
pairing and quantum fluctuations are not the only significant factors for
condensate loss or burst formation. Inclusion of three-body recombination was
found to be inconsequential in all of our simulations, though we do not
consider recent experiments [1] conducted at higher densities
Effect of an atom on a quantum guided field in a weakly driven fiber-Bragg-grating cavity
We study the interaction of an atom with a quantum guided field in a weakly
driven fiber-Bragg-grating (FBG) cavity. We present an effective Hamiltonian
and derive the density-matrix equations for the combined atom-cavity system. We
calculate the mean photon number, the second-order photon correlation function,
and the atomic excited-state population. We show that, due to the confinement
of the guided cavity field in the fiber cross-section plane and in the space
between the FBG mirrors, the presence of the atom in the FBG cavity can
significantly affect the mean photon number and the photon statistics even
though the cavity finesse is moderate, the cavity is long, and the probe field
is weak.Comment: Accepted for Phys. Rev.
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