124,622 research outputs found
Single crystals of metal solid solutions: A study
Report describes growth of silver-alloy crystals under widely varying conditions of growth rate, temperature gradient, and magnetic field. Role of gravitation and convection on crystal substructure is analyzed, as well as influence of magnetic fields applied during crystallization
Application of HCMM data to regional geologic analysis for mineral and energy resource evaluation
Using a thermal-inertia mapping algorithm which provides greater discrimination capability than those in current use, a geologic features was detected in the Cabeza Prieta, Arizona, area. Initially seen on an image formed as a difference of two thermal-inertia images, it was found to be the extension of a bilaterally symmetrical aeromagnetic feature which trends northeast for a distance of at least 1200 km
A high-speed spectrograph shutter
Device can operate in close-open-close mode. Beam splitter placed behind static-slit assembly allows use of more than one camera. Each frame in particular series may be conveniently varied in exposure time and spacing. This can be done independent of other frames in the series. In ''open'' position, shutter transmits light over wide wavelength range
Second order parameter-uniform convergence for a finite difference method for a singularly perturbed linear reaction-diffusion system
A singularly perturbed linear system of second order ordinary differential
equations of reaction-diffusion type with given boundary conditions is
considered. The leading term of each equation is multiplied by a small positive
parameter. These singular perturbation parameters are assumed to be distinct.
The components of the solution exhibit overlapping layers. Shishkin
piecewise-uniform meshes are introduced, which are used in conjunction with a
classical finite difference discretisation, to construct a numerical method for
solving this problem. It is proved that the numerical approximations obtained
with this method is essentially second order convergent uniformly with respect
to all of the parameters
The Entry Incentives of Complementary Producers: A Simple Model with Implications for Antitrust Policy
We model competition between two firms in a vertical upstream-downstream relationship. Each firm can pay a sunk cost to enter the other’s market. For equilibria in which both firms enter, the downstream price can be lower than the joint profit maximizing level, and coordination (e.g., through merger) is anticompetitive.
Geologic application of thermal-inertia mapping from satellite
The author has identified the following significant results. Two night-time thermal images of the Powder River Basin, Wyoming distinctly show a major thermal feature. This feature is substantially coincident with a drainage divide and the southward facing slope appears cooler, suggesting a lower thermal inertia. An initial examination of regional geologic maps provides no clear evidence to suggest what type of geologic feature or structure may be present, although it can be noted that its northeastern end passes directly through Lead, South Dakota where the Homestake Gold Mine is located
Numerical methods for the design and analysis of wings at supersonic speeds
Numerical methods for the design and analysis of arbitrary-planform wings at supersonic speeds are reviewed. Certain deficiencies are revealed, particularly in application to wings with slightly subsonic leading edges. Recently devised numerical techniques which overcome the major part of these deficiencies are presented. The original development as well as the more recent revisions are subjected to a thorough review
- …