49,466 research outputs found
Engineer dynamics and productivity in r and d projects organizational research program
Engineer acquisition and utilization in research and development project
Research program on the organization and management of research and development. Questioning the cost/effectiveness of the R and D procurement process
Cost-effectiveness evaluation of Research and Development proces
Rate constant for deuterium atom recombination calculated by the orbiting resonance theory
Resonance theory for three body recombination kinetics for calculating recombination rate constant of deuterium ato
The role of follow-on contracts in government-sponsored research and development
Role of follow-on contracts in government sponsored research and developmen
Off-design correlation for losses due to part-span dampers on transonic rotors
Experimental data from 10 transonic fan rotors were used to correlate losses created by part-span dampers located near the midchord position on the rotor blades. The design tip speed of these rotors varied from 419 to 425 m/sec, and the design pressure ratio varied from 1.6 to 2.0. Additional loss caused by the dampers for operating conditions between 50 and 100 percent of design speed were correlated with relevant aerodynamic and geometric parameters. The resulting correlation predicts the variation of total-pressure-loss coefficient in the damper region to a good approximation
The importance of habitat quality for marine reserve fishery linkages
We model marine reserve - fishery linkages to evaluate the potential contribution of habitat-quality improvements inside a marine reserve to fish productivity and fishery catches. Data from Mombasa Marine National Park, Kenya, and the adjacent fishery are used. Marine reserves increase total fish biomass directly by providing refuge from exploitation and indirectly by improving fish habitat in the reserve. As natural mortality of the fish stock decreases in response to habitat enhancement in the reserve, catches increase by up to 2.6 tonnes (t).km(-2).year(-1) and total fish biomass by up to 36 t.km(-2). However, if habitat-quality improvement reduces the propensity of fish to move out of the reserve, catches may fall by up to 0.9 t.km(-2).year(-1). Our results indicate that habitat protection in reserves can underpin fish productivity and, depending on its effects on fish movements, augment catches
Violation of the equivalence principle from light scalar fields: from Dark Matter candidates to scalarized black holes
Tensor-scalar theory is a wide class of alternative theory of gravitation
that can be motivated by higher dimensional theories, by models of dark matter
or dark ernergy. In the general case, the scalar field will couple
non-universally to matter producing a violation of the equivalence principle.
In this communication, we review a microscopic model of scalar/matter coupling
and its observable consequences in terms of universality of free fall, of
frequencies comparison and of redshifts tests. We then focus on two models: (i)
a model of ultralight scalar dark matter and (ii) a model of scalarized black
hole in our Galactic Center. For both these models, we present constraints
using recent measurements: atomic clocks comparisons, universality of free fall
measurements, measurement of the relativistic redshift with the short period
star S0-2 orbiting the supermassive black hole in our Galactic Center.Comment: 8 pages, 1 figure, contribution to the 2019 Gravitation session of
the 54th Rencontres de Morion
Slow solitary waves in multi-layered magnetic structures
The propagation of slow sausage surface waves in a multi-layered magnetic configuration is considered. The magnetic configuration consists of a central magnetic slab sandwiched between two identical magnetic slabs (with equilibrium quantities different from those in the central slab) which in turn are embedded between two identical semi-infinite regions. The dispersion equation is obtained in the linear approximation. The nonlinear governing equation describing waves with a characteristic wavelength along the central slab much larger than the slab thickness is derived. Solitary wave solutions to this equation are obtained in the case where these solutions deviate only slightly from the algebraic soliton of the Benjamin-Ono equation
Multiwavelength Studies of PSR J1420-6048, a Young Pulsar in the Kookaburra
We present X-ray, radio, and infrared observations of the 68 ms pulsar PSR
J1420-6048 and its surrounding nebula, a possible counterpart of the gamma-ray
source GeV J1417-6100/3EG J1420-6038. Pulsed X-ray emission at the radio period
is marginally detected by ASCA from a source embedded in the hard spectrum
X-ray nebula AX J1420.1-6049. At radio wavelengths, the pulsar is found to be
strongly linearly and circularly polarized, and the polarization sweep is
measured. A comparison of high resolution ATCA radio imaging of the
Kookaburra's upper wing (G313.6+0.3), which contains the pulsar and the X-ray
nebula, with infrared images suggests the radio emission is partly non-thermal.Comment: 8 pages, 4 figures, to appear in Astrophysical Journal Letter
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