Showing papers by "Juan J. Muñoz-Perez published in 2003"

Multicycle sediments on the continental shelf of Cadiz (SW Spain)

Abstract: The study of recent sedimentation in the Gulf of Cadiz continental shelf (SW Europe) is of interest due to its proximity to the Strait of Gibraltar, where the Atlantic and Mediterranean waters are interchanged and the Western Mediterranean Alpidic Orogen closes through the Gibraltar Arch. The existence of relict materials hinders the distinction of the past and present hydrodynamic regimes in present day sediments. An adequate combination of techniques has allowed the establishment of the multicyclic character of the sediments, as well as the stages undergone by the terrigenous grains. Different stages were identified: eolian and energetic fluvial provenance, chemical alterations acquired in a pedological environment, and a marine coastal origin. To verify the source areas, textural and mineralogical features of marine sediments were compared with those found in geological units from fluvial basins. Three zones were differentiated: (a) a sandy littoral, which receives local sediment supplies; (b) a clayey zone between the Guadalquivir River and Cadiz, controlled by contributions from this river provenant of the Iberian Massif and Betic Mountain range; and (c) a sandy continental shelf, between Cadiz and the Cape of Trafalgar, with a low rate of supplies coming from the Guadalete and Barbate rivers, which include materials from the Occidental Betic Mountain range and Neogene units.

Portable Meter System for Dry Weight Control in Dredging Hoppers

Abstract: A real-time system for monitoring the dry weight contained in the hopper of a given dredge has been both designed and tested. Among the system's most outstanding features, the following may be mentioned: it is of economical acquisition, can easily be set up in a brief period of time, and works independently from any other control systems incorporated into the dredge by the contractor. Moreover, its displacement is determined uninterruptedly. Ultrasound transducers are located on deck for the precise monitoring of cargo volume, and the data are collected through a personal computer and sent, via modem, to the client. The difference between automatic measuring and the standard manual system appeared to have a mean value of 5%. The content of solid matter in the hopper was 53%. Although this system has proven itself fully operative, certain protective measures have to be taken to shield those components exposed to rough maneuvering before the technical supervisors and controllers leave off.