Arterial stiffness is one of the key indicators of cardiovascular diseases, for which an early identification is crucial. Pulse Wave Velocity (PWV) is a widely used parameter to assess arterial stiffness. In clinical practice, it is common use to measure the PWV through the estimation of the Pulse Transit Time (PTT). In this study a comparison among three PTT estimation methods (peak-to-peak, tangent-secant, and cross-correlation) is proposed and applied to waveforms acquired on a novel arterial simulator able to change the stiffness of an arterial surrogate by varying the transmural pressure. After a measurement campaign carried out for several pressure values, the cross-correlation method has been confirmed to be the most robust, with uncertainties below 1.3 %. The operating principle of the arterial simulator has been confirmed since a change in transmural pressure of 25 kPa resulted in a change in PWV mean values of up to 1.7 m/s.

Microgrippers (MGs) are MEMS devices designed specifically for microscopic-scale object manipulation, which makes them ideally suited for implementation in biomedical tissue manipulation applications. This work presents a novel method for estimating the grasping force of a MG prototype equipped with electrostatic rotary comb-drives and Conjugate Surface Flexure Hinges using a cross-approach based on both experimental and a finite element analysis. Firstly, the torque exerted by the microactuators, necessary to deform the MG has been evaluated. The rotation of the microactuators is measured in the experimental analysis through an image analysis approach developed by the Authors from videos acquired by a camera mounted on a trinocular optical microscope, while the hinge stiffness has been determined using numerical simulations. This torque provided an initial estimate of the grasping force potential. Subsequently, in order to evaluate the force that the jaws of the MG are capable of applying in grasping operations, experimental tests have been carried out on a human hair with a diameter of (86 ± 3) µm. The results obtained show that the jaws of the device apply a maximum force of (1.42 ± 0.18) µN while grasping the hair.

Continuous variable transmission (CVT) is a widely used technology for two-wheeler applications due to its cost-effectiveness, lightweight, and reduced size. This kind of transmission involves the accurate matching of the system with the engine characteristics. This paper analyzes the typical design procedure used to develop the transmission system and evaluates the current approach’s critical issues. The paper aims to identify a possible path to improve the system and its customization capacity. It is identified that the critical design stage is the identification of the correct sliding profile for the half pulley of the front assembly of the system. Then, the geometrical parameters of the transmission are accurately identified through a detailed kinematic analysis. The presented kinematic analysis is propaedeutic for developing a mathematical model that defines the rollers’ sliding profile according to the vehicle’s performance.

Several car manufacturers have encountered corrosion in certain mechanical components caused by chlorine in fuel. The current regulations governing the quality of fuel allowed for trade are briefly described. Next, this paper analyzes the possible origin of chlorine in damaged components. In particular, the phenomenon of corrosion found in EGR valves and EGR coolers is analyzed. The analyses conducted to determine the nature of the corrosion and its origin are illustrated. Finally, the effects of the phenomenon on engine operation are analyzed, depending on the type of damaged component.

This work presents the development of a measuring instrument capable of assessing the possible presence of critical permanent deformations on the connecting rod in hybrid cars equipped with gasoline-powered internal combustion engines. The permanent deformation can be due to incorrect fueling and cause a progressive engine failure through the breaking of one or more connecting rods. The measuring tool developed is a non-invasive, low-cost system and permits the detection of the incipient damage without dismantling the engine, thus assuring a time-saving approach. The instrument is composed of a mechanical system and an electronic interface that permits easy use during measuring operations and the possibility to store the data collected. An experimental campaign was implemented to validate the measurement system’s capability to detect this type of damage and to determine a threshold beyond which it is necessary to proceed with the replacement of connecting rods. The results show the optimal ability to differentiate between usual technological variability of the piston stroke and the range that can be connected to the anomaly studied. The system is also able to permit the measurement of a whole engine in less than 20 min.