Abstract: The present invention relates to the concept of a stress digital twin. The stress digital twin of an individual is a digital, i.e. computer-implemented system for monitoring a stress level of a living individual on the basis of at least data directly measured on the body of the living individual and by performing a thermodynamic evaluation of the stress entropic load. The stress entropic load is a thermodynamic parameter representing an amount of entropy generated within the living individual due to adaptation to a whole set of environmental influences in a given scenario at a given point of time. Based on a comparison with pre-collected reference data (library data), the invention triggers actions such as withdrawal or replacement of individuals acting in a given scenario or the issuing of alerts.

Abstract: An improved pilot control relay valve is disclosed to monitor pressure conditions in a pressurized system and to cause the system to shut down in response to detection of operating pressures excessive of an acceptable pressure range. Accurate monitoring is provided for by dual-piston action, with one of the pistons actuating a visual indicator mounted on the slide valve of the control relay valve, and with the second piston coaxially mounted within the first piston.