Groundwater contamination: risk management and assessment for landfills in Mar del Plata, Argentina

 This study presents a program for risk management in the contamination of groundwater resulting from leachate in landfills at Mar del Plata (Argentina). The program includes prediction, prevention, monitory observation and mitigation as actions that must be taken prior to, during, and after contamination occurs. This routine aids in the identification of weak points and failures of the program for those who are in charge of making decisions, and will allow better use of limited financial and technical resources based on planning, thus minimizing disconnected determinations. Results of the prediction stage were confirmed through monitoring. The presence of a plume of contamination more than 100 m from the landfill was shown, thus proving that implementation of a monitoring plan to follow the development of the contaminated plume must be implemented, particularly in populated areas which depend on residential wells for their water supply. Received: 8 May 2000 · Accepted: 14 August 2000     

Determination of the original shape of pulsations from their spectra

Zusammenfassung Es wird eine einfache auf der Symmetrie der Grundformeln der Fourierschen Transformation gegründete Methode, wie von den Spektralfunktionen zur ursprünglichen Pulsationsform zu gelangen, beschrieben. Mit dieser Methode wird die durchschnittliche Form der Pi2-Pulsationen konstruiert. Diese idealisierte Pulsation hat dieselben Eigenschaften wie ein statistisches Ensemble von Pulsationen. Der wirkliche Verlauf der Intensit?t des magnetischen Feldes bei Pi2-Pulsationen wird durch die Methode aus den Induktionsregistrierungen abgeleitet. Die berechnete Kurve zeigt starke Korrelation mit der direkten Registrierung der Intensit?t des magnetischen Feldes.

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Address: Boční II, Praha 4-Spořilov.     

Approximate spectral analysis by least-squares fit

An approximate method of spectral analysis called successive spectral analysis based upon the mean-quadratic approximation of an empirical function by generalised trigonometric polynomial with both unknown frequencies and coefficients is developed. A few quotations describing some properties of the method as well as one of the possible methods for numerical solution are given.     

Diffusive-Shock-Accelerated Interplanetary Ions At Several Energies During the Solar Cycle 21 Maximum

The most intense energetic particle (mainly proton) events in the energy range 36–1600 keV, during the years of maximum activity of solar cycle 21 (1978 to 1982), have been studied with regard to their spectra, temporal profiles, source location at the Sun, interplanetary plasma parameters and interplanetary magnetic field topology. In all the events, the particles were accelerated by the 'Diffusive Shock' acceleration mechanism, because all the events were 'long-duration events', shock-associated, and their spectra fitted to a power-law energetic particle spectrum dJ/dE E^-\gamma with the exponent values ranging from 1.25 up to 1.94, with a mean value of 1.60 ± 0.06. We also show that the spectral indexes are related to the shock properties by a linear expression. The solar sources were located on a wide longitudinal belt extending from 50^ W up to 73^ E. Neither the spectral indexes nor the shock parameters present any dependence on the source location at the Sun. Finally, only one event showed the complete set of properties that characterize the presence of a magnetic cloud associated with the event.