14,251 research outputs found
A demonstration of ERTS-1 analog and digital techniques applied to strip mining in Maryland and West Virginia
The largest contour strip mining operations in western Maryland and West Virginia are located within the Georges Creek and the Upper Potomac Basins. These two coal basins lie within the Georges Creek (Wellersburg) syncline. The disturbed strip mine areas were delineated with the surrounding geological and vegetation features using ERTS-1 data in both analog (imagery) and digital form. The two digital systems used were: (1) the ERTS-Analysis system, a point-by-point digital analysis of spectral signatures based on known spectral values, and (2) the LARS Automatic Data Processing System. The digital techniques being developed will later be incorporated into a data base for land use planning. These two systems aided in efforts to determine the extent and state of strip mining in this region. Aircraft data, ground verification information, and geological field studies also aided in the application of ERTS-1 imagery to perform an integrated analysis that assessed the adverse effects of strip mining. The results indicated that ERTS can both monitor and map the extent of strip mining to determine immediately the acreage affected and indicate where future reclamation and revegetation may be necessary
The state space of short-range Ising spin glasses: the density of states
The state space of finite square and cubic Ising spin glass models is
analysed in terms of the global and the local density of states. Systems with
uniform and gaussian probability distribution of interactions are compared.
Different measures for the local state density are presented and discussed. In
particular the question whether the local density of states grows exponentially
or not is considered. The direct comparison of global and local densities leads
to consequences for the structure of the state space.Comment: 18 pages (including 6 figures); submitted to Z.f.Physik
Evidence for retrograde lithospheric subduction on Venus
Though there is no plate tectonics per se on Venus, recent Magellan radar images and topographic profiles of the planet suggest the occurrence of the plate tectonic processes of lithospheric subduction and back-arc spreading. The perimeters of several large coronae (e.g., Latona, Artemis, and Eithinoha) resemble Earth subduction zones in both their planform and topographic profile. The planform of arcuate structures in Eastern Aphrodite were compared with subduction zones of the East Indies. The venusian structures have radii of curvature that are similar to those of terrestrial subduction zones. Moreover, the topography of the venusian ridge/trench structures is highly asymmetric with a ridge on the concave side and a trough on the convex side; Earth subduction zones generally display the same asymmetry
Unusual localisation effects in quantum percolation
We present a detailed study of the quantum site percolation problem on simple
cubic lattices, thereby focussing on the statistics of the local density of
states and the spatial structure of the single particle wavefunctions. Using
the Kernel Polynomial Method we refine previous studies of the metal-insulator
transition and demonstrate the non-monotonic energy dependence of the quantum
percolation threshold. Remarkably, the data indicates a ``fragmentation'' of
the spectrum into extended and localised states. In addition, the observation
of a chequerboard-like structure of the wavefunctions at the band centre can be
interpreted as anomalous localisation.Comment: 5 pages, 7 figure
Investigation of electrochemistry of high energy compounds in organic electrolytes, May 1 - October 31, 1965
High energy compounds in organic electrolytes - electrochemical and chemical properties of cyclic esters, gamma butyrolactone, gamma valerolactone, and propylene carbonat
Investigation of electrochemistry of high energy compounds in organic electrolytes Third progress report, Nov. 1, 1965 - Apr. 30, 1966
Electrochemical properties, and chemical reactions between cyclic esters and certain metal
Investigation of electrochemistry of high energy compounds in organic electrolytes, november 1, 1964 - april 30, 1965
Conversion by electrochemical process of chemical to electrical energy - high energy compounds in organic electrolytes and cathode material
Belief Hierarchical Clustering
In the data mining field many clustering methods have been proposed, yet
standard versions do not take into account uncertain databases. This paper
deals with a new approach to cluster uncertain data by using a hierarchical
clustering defined within the belief function framework. The main objective of
the belief hierarchical clustering is to allow an object to belong to one or
several clusters. To each belonging, a degree of belief is associated, and
clusters are combined based on the pignistic properties. Experiments with real
uncertain data show that our proposed method can be considered as a propitious
tool
Electron effective mass in AlGaN alloys determined by mid-infrared optical Hall effect
The effective electron mass parameter in Si-doped AlGaN is
determined to be from mid-infrared optical Hall
effect measurements. No significant anisotropy of the effective electron mass
parameter is found supporting theoretical predictions. Assuming a linear change
of the effective electron mass with the Al content in AlGaN alloys and
for GaN, an average effective electron mass of
can be extrapolated for AlN. The analysis of mid-infrared
spectroscopic ellipsometry measurements further confirms the two phonon mode
behavior of the E(TO) and one phonon mode behavior of the A(LO) phonon
mode in high-Al-content AlGaN alloys as seen in previous Raman scattering
studies
- …