Ecole Des Mines De Paris Research Articles

A Uranium Geochemical Study at the Natural Analogue Site of Needle's Eye. SW Scotland

ABSTRACTA detailed study is being carried out at the Needle's Eye locality, on the Solway Firth, into the movement and fixation of U and its daughter isotopes. The site contains pitchblende veins, some of which have acted as a source of soluble uranium flowing into and through estuarine silts laid down in the last 2000 years or so. A section through these has provided samples for detailed analysis by X-ray fluorescence and neutron activation techniques. High resolution gamma spectrometry has contributed information on the distributions and disequilibria between uranium and its daughters. These data have been combined with analyses from groundwaters to produce a geochemical model of the origins of the U radioisotope distributions and transport mechanisms. There are thought to be two main inputs of dissolved U(VI) into this system; the surface flow of groundwater from the exposures of the mineralisation in the cliff, and upward flow from the bedrock below. The fixation of U in the sediments is controlled by the presence of organic matter in the upper humic layers, and by an iron oxy-hydroxide sorption reaction in the deeper silts at about 110cm. This concentration of U in the silt is divorced from the sub U-234 daughters. In contrast. Th is coherently associated with its daughters within detrital resistate phases. This study is a prelude to a more rigorous modelling investigation in collaboration with the Ecole des Mines de Paris.

Télédétection des paysages africains par Landsat et Météosat.

Remote sensing of Africans landscapes by Landsat and Meteosat : central Africa areas, N'Djamena area (Chad) and Annaba area (Algeria). Land use cartography is based on the processing of Landsat and Meteosat satellites. The environmental cartographic results are based on multitemporal analysis and processing of multispectrals bands (visible-infrared and surface temperatures). The geographical taxonomy is based on the joint processing of satellites multispectral data and ground truth observations. The supervised computer classifications were done at C.T.A.M.N. Ecole des Mines de Paris. The proper use of multitemporal satellite information will lead to the future production of regional atlases into geographical land use data bases of environment as well as human activities.

Kriging in the design of streamflow sampling networks

Kriging is of particular interest in network design because of its ability to estimate streamflow values using existing stations. Another possibility offered by kriging is the estimation of variance reduction gained by addition of fictitious stations in regions of high variance. In this article we give a brief description of kriging theory as developed at the Ecole des Mines de Paris. In order to improve and optimize the Quebec streamflow recording network design we kriged specific streamflows with a given return period over the Quebec province, using the data observed at existing stations. For the evaluation of the given return period flow and its sampling variance at each gauged site we use the log Pearson type 3 distribution model. Kriging is an optimal estimation technique, in terms of minimum variance, and contrary to other methods it gives an estimation variance for any point in the kriged domain, which is essential in network design.

A conceptual deterministic analysis of the kriging technique in hydrology

A stochastic approach to interpolating sparse observation records in hydrology referred to as the ‘kriging technique’ has recently been developed by Matheron (1969, 1970) and systematically used in the field by the Ecole des Mines de Paris. Distinct primary features of this method are supposed to be its predictive reliability and its ability to provide an estimation error. In the present paper a deterministic analysis for the kriging technique is given without resorting to a statistical framework. It turns out that a close relationship with the most traditional interpolation schemes may easily be found. The formulation shows that in relation to other commonly used methods, any claim to produce more accurate estimates fails to be proven, since an arbitrary component is necessarily introduced by the decision process of selecting an operative model. It is recognized that a distinct and unique advantage of the kriging technique is its ability to provide an assessment of the interpolation error. An attempt is also made to give a deterministic interpretation for the main trend. The results show that the use of this concept involves an additional component of arbitrariness whose impact upon the final outcome can hardly be predicted a priori. The conclusions of the present analysis suggest that in practical applications the interpretation model is not improved by the use of a main trend, unless its expression reflects some additional information related to the general hydrologic context but not included in the available observations.

Panel discussion on processing

Abstract Dr. J. Chauffoureaux (Solvay, Brussels, Belgium): Professor Menges will speak first about research now being carried out in Aachen. Dr. Avenas will talk about calendering and other work he is doing at the Ecole des Mines de Paris. Finally, Dr. Gould will discuss the relationship between processing and the fatigue properties of PVC.

Creep Fatigue Short Crack Propagation In AStress Gradient

Creep Fatigue Short Crack Propagation In AStress Gradient

The Training of Managers at a French Ecole

L'EcoLE des Mines de is not a school of mines, in spite of its name, nor is it a business school, in spite of the title of this paper. Its nature can be understood in the context of the French system of higher education, which consists of two kinds of institution with little or no connexion between them: 1. The universities, which are similar to those which exist in most countries and are centralized under the Ministry of Education. 2. The schools of engineering, known as which are also public institutions but under various authorities such as: Ecole Polytechnique (Ministry of War), Ecole des Ponts et Chaussees (Ministry of Equipment), Agronomic Institute (Ministry of Agriculture), etc. Some of these come under the authority of the Ministry of Education (e.g. Ecole Centrale), but they possess a greater degree of autonomy than the universities. The Ecole des Mines is one of the second category and is under the authority of the Ministry of Industry. The main characteristics of the Grandes Ecoles, as compared with the universities, are the limited number of students, the highly discriminative selection and the stress on general training. For historical reasons which I will not go into here, most responsible positions in industry and government offices are held by former students of the Grandes Ecoles. This fact, combined with the breadth of opportunity and the security which are offered to the graduates, accounts for the great attraction of these schools. The students are selected by means of a difficult entrance examination in which the most important subjectis basic mathematics. The examination takes place two or three years after the end of the students' secondary education, i.e. at an average age of 19 or 20. Roughly 1500 students compete for places at the Ecole des Mines de Paris and only 60 are admitted. Of course most of them compete for admission to other schools, but the Ecole des Mines takes its students from among the best, as is indicated by the fact that the last one admitted usually ranks between 120th and 150th on the list. It follows that our curriculum is based on the fact that our students belong to the elite of the mathematical brains of their generation and that they will have managerial responsibilities in most branches of industry. Of course they will be primarily engineers and, at least during the first years of professional practice, they will have technical responsibilities in production or research. Although no