Physics   > Home   > Entropy: Thermodynamics – Energy – Environment – Economy   > Issue

Vol 3 - Issue 2

Entropy: Thermodynamics – Energy – Environment – Economy

List of Articles

Major electric constraint of a synchronous wound rotor generator associated with a charged wind generator and blades ray influence on the group starting wind speed

System of mechanical energy conversion into electric energy includes a motor, a generator and a load. A mechanical interface placed between the motor and the generator adapt the two links rotation speed, while an electric interface connecting generator and load ensures the frequency and the load electric signals levels stability. The chains synchronous wound rotor generator electric constraints and the group starting wind speed are studied by referring the load and the electric interface to the generator and by solidarizing the generator and the wind mill. Betz limit power, affected by the site attenuating factor is used like motive power of the group. Wind speed instability converts the generator into a variable frequency source supplying a RL cell modelling the referred load and electric interface. Simulation by programming under Scilab with data close to that real generator revealed overcurrent in the generator for for high speeds of the wind and an increase of starting wind speed of the group for a blades ray reduction. This justifies the interfaces and the control units need in the group.

Mathematical simulation of aggregative processes: generalization of the IdEP-IdLA model

The so-called IdEP-IdLA mathematical model, used to theoretically investigate the chemistry of aggregative processes, is based on specific hypotheses whose purpose is to schematize both the physical description of the base material and the ways in which compounds are formed. This study is part of the abstraction process underlying the construction of the model and aims to introduce a generalization that increase the solidity of the entire theoretical approach. Such a generalization demonstrates, in particular, the resilience of the model against a wide range of possible ways of spatial aggregation of the base material. After having described the proposed changes and having made the necessary formal adjustments to the theoretical relations produced by the model, the study focuses on the evaluation of the impact that the new and more general hypotheses have on the results obtained previously, confirming the validity in principle of the conclusions already reached.

Other issues :


Volume 20- 1

Issue 1
Issue 2
Issue 3
Issue 4


Volume 21- 2

Issue 1
Special issue
Issue 3


Volume 22- 3

Issue 1
Issue 2