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Post-sedimentary transformations have masked or completely obliterated the structures and textures of Precambrian carbonate rocks. Therefore, methods of classification of the carbonate rocks founded on the observation of primary structures or textural characteristics are ill-adapted. Consequently, only certain geochemical classification methods allow us to distinguish the various rock-types in the case of Neoproterozoic carbonates. After presenting the most suitable geochemical classifications, we propose a new classification into 14 groups based on a regular ternary diagram with computerized data input. For each sample of carbonate rock, analysis of calcium and magnesium contents allows us to calculate the input data for our diagram i.e. the percentages of Calcite, Dolomite and Insoluble Residue. To automate the application of this diagram, input parameters are created in a descriptive file “Roches.ternaires.txt” using an option called “Ternaires” in the “Diagrammes” software developed by Roland Simler. Thirty cap carbonates of Africa are used to validate this new method.
Medellin is a 3.5 M inhabitant city located in an Andean valley in northwestern Colombia. Its initial prosperity was due to agriculture and cattle-raising carried out in the valley itself and sold to the surrounding gold mining fields. The investment of these monies in coffee plantations and industry boosted the city development, accelerated urban growth, and since the middle of twentieth century, relegated food production to surrounding regions, which are also responsible for almost the totality of natural resource supply: water, electricity, food, building and industrial raw materials. Among the problems which will have to be solved in order to reach a sustainable development are relocation of population living in areas exposed to natural risks, improvement of road communications with surrounding regions and of internal public transportation and pollution control.
This paper aims at describing the theoretical fundamentals of a
reciprocity-based ultrasonic measurement model. This complete inspection
simulation can be decomposed in two modeling steps, one dedicated to transducer
radiation and one to flaw scattering and echo synthesis. The physical meaning
of the input/output signals used in these two modeling tools is defined and the
theoretical principles of both field calculation and echo computation models
are then detailed. The influence on the modeling results of some changes in the
simulated configuration (as the incident angle) or some input signal parameters
(like the frequency) are studied: it is thus theoretically established that the
simulated results can be compared between each other in terms of amplitude for
numerous applications when changing some inspection parameters in the simulation
but that a calibration for echo calculation is generally required.
A computer code for simulation of
groundwater flow and transport is described. Both porous and fractured media
are handled by the code. The main intended application is the analysis of a
deep repository for nuclear waste and for this reason flow and transport in a
sparsely fractured rock is in focus. The mathematical and numerical models are
described in some detail. In short, one may say that the code is based on the
traditional conservation and state laws, but also embodies a number of
submodels (subgrid processes, permafrost, etc). An unstructured Cartesian grid
and a finite volume approach are the key elements in the discretization of the
basic equations. A multigrid solver is part of the code as well as a
parallelization option based on the SPMD (Single-Program Multiple-Data)
method. The main application areas are summarized and an application to a deep
repository is discussed in some more detail.