The optimal design of excitation signal is a procedure of generating an informative input signal to extract the model parameters with maximum pertinence during the identification process. The fractional calculus provides many new possibilities for system modeling based on the definition of a derivative of noninteger-order. A novel optimal input design methodology for fractional-order systems identification is presented in the paper. The Oustaloup recursive approximation (ORA) method is used to obtain the fractional-order differentiation in an integer order state-space representation. Then, the presented methodology is utilized to solve optimal input design problem for fractional-order system identification. The fundamental objective of this approach is to design an input signal that yields maximum information on the value of the fractional-order model parameters to be estimated. The method described in this paper was verified using a numerical example, and the computational results were discussed.

The objective of this study is to recover sludge from the Dar Gueddari sewage treatment plant and use it in the cultivation of corn in the open field on clay soil. To do this, four doses were tested against two types of controls: a control without addition of sludge and another with the addition of nitrogen-based fertilisers (200 kg N, 100 kg P and 100 kg K). The short-term effects indicated that the application of the sludge had a beneficial effect on the fertilising qualities of the soil and therefore on the crop yield. The monitoring of the agronomic parameters of the maize plant showed that the growths and the yields varied according to doses of the sludge. In grain yield, the difference between plot E4 and E0 was around 3.3 Mg∙ha ^–1. In addition, the plots treated with large sludge doses experienced improvements in total nitrogen and organic matter. During the second season, the results obtained showed decrease in nutrients (nitrogen and phosphorus). It emerged from the C:N ratio which was 8. This indicated a good mineralisation of the organic matter (OM) which was average of 2.48 ±0.04% and 2.5 ±0.01%, respectively in the E4 and E5 treatments. In addition, the amounts of N, P and Ca in dry matter (DM) increased with increasing the dose of sludge. During the 2017 season, the highest values were detected in plot E5 with averages of 1.6% in N and 0.53% in P.

The obtained results showed that grain aphid (Sitobion avenae Fabr.) feeding caused an increase of the total protein content and a decrease of soluble protein level in the ears of both studied winter triticale cultivars (i.e. susceptible cultivar Grado and relatively resistant - Lasko). Moreover, the content of amino acids in soluble protein increased in Grado plants infested with the aphid, and reduced - in Lasko.