1,721,257 research outputs found
Ascent trajectories of multistage launch vehicles. Numerical optimization with second-order conditions verification
No full textMultistage launch vehicles are employed to place spacecraft and satellites in their operational orbits. Trajectory optimization of
their ascending path is aimed at defining the maximum payload mass at orbit injection, for specified structural, propulsive, and
aerodynamic data. This work describes and applies a method for optimizing the ascending path of the upper stage of a specified
launch vehicle through satisfaction of the necessary conditions for optimality. The method at hand utilizes a recently introduced
heuristic technique, that is, the particle swarm algorithm, to find the optimal ascent trajectory. This methodology is very intuitive
and relatively easy to program. The second-order conditions, that is, the Clebsch-Legendre inequality and the conjugate point
condition, are proven to hold, and their fulfillment enforces optimality of the solution. Availability of an optimal solution to the
second order is an essential premise for the possible development of an efficient neighboring optimal guidance
A biomonitoring study: trace metals in algae and molluscs from Tyrrhenian coastal areas.
No full text
Biological monitoring: lichens as bioindicators of air pollution assessment - a review
No full textOften as part of environmental impact studies and, above all, to obtain authorisations in accordance with prescriptions from the Ministry for the Environment (Italy), surveys and controls that use biological indicators are required. This is because such indicators are valid instruments for evaluating the quality of the air ensuing from the subject (often an industrial plant) of the Environmental Impact Assessment (EIA).
In this context, this paper aims to analyse some of the theoretical aspects of biological monitoring and to provide a progress report on the use of lichens as bioindicators of air quality, with a particular eye to the situation in Italy. The object of this paper is that of pointing out the most important lines in the current state of knowledge in this field, evaluating the methodological applications and their advantages/disadvantages with respect to traditional surveying methods
Controllo dell’esposizione alla formaldeide in relazione alla nuova classificazione IARC.
No full textSEZIONE POSTER (QP12)SECTION (QP12
A biomonitoring study: trace metals in seagrass, algae and molluscs in a marine reference ecosystem (southern Tyrrhenian sea)
No full textBIOACCUMULO DI METALLI PESANTI IN UN INDICATORE BIOLOGICO (POSIDONIA OCEANICA (L.) DELILE)
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