[en] The presence of arsenic and mercury in some chilean facial cosmetics was investiged. Since in Chile there is no regulations dealing with the maximum permisible concentration of some chemical elements in cosmetics products, the national industry control neither the presence nor the quantity, if any, of those elements. The study was performed on compact or powder eye shadows by means of instrumental neutron activation analysis. The samples were analized without any chemical treatment and with minimum manipulation to avoid any possible contamination. A total of 67 samples from 9 different cosmetic industries were analysed. Arsenic was detected and determined quantitatively in 46 samples, ranging from 0.32 to 136 ppm. Mercury was not detected in any sample. The contamination of arsenic is due to the high concentration of this element in some of the raw material used in the manufacturing of the cosmetics, as was demonstrated by the analysis of these materials. (EC)

[en] We have analysed data taken with a prototype of the ALEPH electromagnetic calorimeter. The aim of this work was to find criteria to obtain the lowest value of the π/e rejection coefficient with a good efficiency to the electrons. At the same time we have measured the energy resolution and the spatial resolution of our apparatus. The experimental results were compared with the predictions of the simulation programs: EGS for the electromagnetic showers and GHEISHA for the hadronic one's

[en] Recently it takes a serious look at fuel cell vehicles, a leading candidate for next-generation vehicle propulsion systems. The green house effect and air quality are pressing to the designers of internal combustion engine vehicles, owing to the manufacturers to find out technological solutions in order to increase the efficiency and reduce emissions from the vehicles. On the other hand, energy source used by currently propulsion systems is not renewable, the well are limited and produce CO₂ as a product from the combustion process. In that situation, why fuel cell is an alternative of internal combustion engine?

[en] The political events occurred in the last years of the 18th century, the Independence war and the reign of Fernando VII, ruined the Spanish scientific panorama, physics included. During the 19th century, the national scientific production was restricted to textbooks and popularization works. Two kinetic derivations of the law of perfect gases corresponding to a textbook and a book about steam engines from the viewpoint of thermodynamics are presented and discussed. (Author) 16 refs

No abstract available

[en] The control rods are calibrated with several steps traditionally small reactivity. An innovation in this process is continuously withdrawing the control rod from the reactor core to the periphery. Innovation is done by 10% of the time for the usual procedure, which can result in cost savings in commercial reactors.

[en] This work describes the experimental way followed for getting the calibration of a NE213 detector with a beam of neutrons from the J.E.N. 2 MeV Van de Graaff and using at once pulse shape discrimination. Detector has been used for measuring the spectrum of the fast reactor CORAL-1. There is also included an experimental method in order to get with precision where the Compton edge is placed on the electron spectrum. (Author) 9 refs

[en] BWR stability can be treated with reduced order dynamical models. When the parameters of the model came from dynamical models. When the parameters of the model came from experimental data, the predictions are accurate. In this work an alternative derivation for the void fraction equation is made, but remarking the physical structure of the parameters. As the poles of power/reactivity transfer function are related with the parameters, the measurement of the poles by other techniques such as noise analysis will lead to the parameters, but the system of equations is non-linear. Simple parametric calculation of decay ratio are performed, showing why BWRs become unstable when they are operated at low flow and high power. (Author)

[en] The main objective of the work consisted of the development and application of a procedure of cleaning chemical that would significantly reduce the level of obstruction of the plates stand and part of the fouling in the tubes-free zone, respecting a value of admissible maximum corrosion. This procedure also aim preserve optimal operating conditions while keeping all security criteria, without having to resort to a new chemical cleaning for a minimum of 4 cycles of exploitation. (Author)

[en] This paper presents the actions implemented in successive iterations and the remarkable results achieved so far in this line of action. (Author)