2,618 research outputs found
Phase space characteristics of fragmenting nuclei described as excited disordered systems
We investigate the thermodynamical content of a cellular model which
describes nuclear fragmentation as a process taking place in an excited
disordered system. The model which reproduces very well the size distribution
of fragments does not show the existence of a first order phase transition.Comment: 14 pages, TeX type, 7 figure
Effet du couvert forestier sur la précision d'un système de positionnement global différentiel
Effect of forest canopy on the accuracy of a differential global positioning system (dGPS). The possibilities to use dGPS (differential global positioning system) for forest mapping are analyzed. The efficiency of dGPS in forest condition is linked to canopy interference, which intercepts signals sent by some of the satellites or reflect them (multipathing). Two types of equipment have been tested: a Trimble Svee Six coupled with a RDS differential receiver and a Trimble SK8 coupled with an OMNISTAR differential receiver. Recordings have been achieved according to two modes: static (recording on one spot during one minute) and cinematic (moving continuously along the stand limits). Two types of forest canopy were compared: light canopy made of young poplar plantation with few obstacles in the vicinity, and closed canopy of mature spruce stand edged with other mature stand. Cinematic mode efficiency is higher than static one (mean errors are respectively 3.1 m and 9.1 m). In the same way positioning is more accurate for the stand with light canopy than for the other one (mean errors are respectively 2.9 m and 9.4 m). Difference between recording modes are probably due to multipathing effect that filtering algorithm integrated in the GPS receivers are not able to remove in static mode. The efficiency of differential signal reception is also different for the two stands: 1.3/ and 20.5/ of missing differential signal respectively in the light and dense canopy conditions
The genus Elasmopus on the coast of Brazil with description of Elasmopus besnardi n. sp., and E. fusimanus n. sp. (Crustacea, amphipoda)
Neste trabalho apresentamos os anfípodos do gênero Elasmopus, que são representados na coleção da Estação de Hidrobiologia do Instituto Oswaldo Cruz, e entre eles temos a honra de dedicar uma espécie ao Prof. W. Besnard. Assim este trabalho representa, de certo modo, uma contribuição aos resultados da Expedição do navio 'Baependi', realizada em 1950, à Ilha da Trindade
PROPERTIES OF HOT NUCLEAR MATTER
The properties of cold and hot nuclear matter are studied in the frame of the Brueckner theory, extended to finite temperature. We limit ourself to the BHF approximation. The basic ingredient is the Paris potential supplemented by the introduction of three-body forces coming from the exchange of π and ρ mesons. Particular attention is paid to one-body properties namely the single-particle energy spectrum, the effective mass and the mean free path. We evaluate and discuss the level density parameter a which is closely related to the calculated entropy. In a first approach, the temperature and density dependence of a two-body properties, the effective interaction, is analysed
Expert system supervisory control of the Wheal Jane tin concentrator
K. A. Lewis, P. Tucker, A. Wells, and G. Le Jeune, 'Expert System Supervisory Control of the Wheal Jane Tin Concentrator', paper presented at the Second Symposium on Personal Computers in Industrial Control, 21-22 November 1990, DTI Warren Spring Laboratory, Stevenage, HERTS, UKThis paper reports computer simulation and modelling techniques used at the Wheal Jane tin mine in Cornwall to improve processing efficiency.Non peer reviewedFinal Published versio
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