Swinging Atwood's Machine: Experimental and Theoretical Studies

A Swinging Atwood Machine (SAM) is built and some experimental results concerning its dynamic behaviour are presented. Experiments clearly show that pulleys play a role in the motion of the pendulum, since they can rotate and have non-negligible radii and masses. Equations of motion must therefore take into account the inertial momentum of the pulleys, as well as the winding of the rope around them. Their influence is compared to previous studies. A preliminary discussion of the role of dissipation is included. The theoretical behaviour of the system with pulleys is illustrated numerically, and the relevance of different parameters is highlighted. Finally, the integrability of the dynamic system is studied, the main result being that the Machine with pulleys is non-integrable. The status of the results on integrability of the pulley-less Machine is also recalled.Comment: 37 page

Templates and Framed Braids

We show how a template for a dynamical system can be uniquely specified by a framed braid. This leads to a homological classification of strange attractors in terms of an associated linking matrix

Utilizzo dei ricevitori GNSS a basso costo per l’esecuzione di rilievi topografici di elevata precisione

The availability of low-cost GNSS receivers opens up new possibilities for performing precision topographic surveys. To achieve acceptable survey precision, it is necessary to use the services provided by a network of permanent stations. The services consist of a stream of differential correction data of the detected positions, transmitted in the RTCM format (Radio Technical Commission for Maritime Services, international standard) which are received through the NTRIP protocol following an authenticated connection to the network site