7,990 research outputs found
A mineral reconnaissance survey of the Abington-Biggar-Moffat-area, south-central Scotland
Panned heavy mineral concentrates, mostly obtained from stream sediments,
were collected from 195 sites in the Abington-Biggar-Moffat area. The project
area, which lies immediately east of the formerly important mining district of
Wanlockhead-Leadhills, covers approximately 500 km2 of the north-central
sector of the Southern Uplands. It incorporates the Hart Fell range of hills,
the headwaters catchment for the River Tweed and River Annan, some
tributaries of the River Clyde, and, to the east, the Culter Water, Talla
Reservoir, Megget Water and the head of the Ettrick valley.
Numerous new occurrences of lead, zinc, copper and barium minerals were
found and nine areas are recommended for further investigation. Minor amounts
of baryte and traces of cupriferous pyrite were identified in the basal breccia of
the-New Red Sandstone deposits in Annandale. The mercury mineral, cinnabar,
was identified for the first time in Scotland, occurring in trace amounts in
stream sediment concentrates in the Coulter area close to the Southern Upland
Fault. Chromiferous spine1 was recognised as a major constituent in the
majority of panned samples. It is present as a detrital mineral in greywackes
but must have been originally derived from ultrabasic rocks. An unusual mineral
widely dispersed in trace amounts is corundum (including some gem-quality
sapphire). Historical references (Lauder Lindsay, 1868-9, 1871) to a wide
distribution for particle gold were confirmed and many new occurrences found.
A local provenance for the element is now considered certain. Some placer
concentration of gold and chromiferous spine1 is likely in the alluvium of
the valleys of the River Tweed and the Megget Water.
Six greywacke formations, previously defined in other parts of the Southern
Uplands, were mapped in the project area, each distinguished by a characteristic
lithology and heavy mineral content
The high energy limit of the trajectory representation of quantum mechanics
The trajectory representation in the high energy limit (Bohr correspondence
principle) manifests a residual indeterminacy. This indeterminacy is compared
to the indeterminacy found in the classical limit (Planck's constant to 0)
[Int. J. Mod. Phys. A 15, 1363 (2000)] for particles in the classically allowed
region, the classically forbiden region, and near the WKB turning point. The
differences between Bohr's and Planck's principles for the trajectory
representation are compared with the differences between these correspondence
principles for the wave representation. The trajectory representation in the
high energy limit is shown to go to neither classical nor statistical
mechanics. The residual indeterminacy is contrasted to Heisenberg uncertainty.
The relationship between indeterminacy and 't Hooft's information loss and
equivalence classes is investigated.Comment: 12 pages of LaTeX. No figures. Incorporated into the "Proceedings of
the Seventh International Wigner Symposium" (ed. M. E. Noz), 24-29 August
2001, U. of Maryland. Proceedings available at
http://www.physics.umd.edu/robo
Passive venting technique for shallow cavities
A device is introduced for reducing drag and store separation difficulties caused by shallow cavities on aircraft in supersonic flight consisting of a group of hollow pipes the same length as the cavity. The pipes are attached to the cavity floor so as to allow air to flow through the pipes. This device allows air to flow through the pipes opposite to the direction of flow outside the pipes. This results in reduced drag and improved store separation characteristics
- …