Calibration of hydrophones taking into account the conditions of their use

A measuring facility for reproducing a unit of sound pressure at frequencies of 1–500 Hz in the temperature range of 0.5–35 °С with excessive static pressures up to 60 MPa is described. The measuring facility was created in order to expand the functionality of the State primary standard GET 55-2017. The expediency of simulated ocean conditions in GET 55-2017 under hydrophone calibration, the principles of operation and the metrological characteristics of the measuring facility are discussed. Features of the measuring procedure for calibrating the hydrophone are given.

Concept and setup of a multi-component facility for force and torque in the range of 1 MN and 2 kN·m

This article describes the design of a measuring facility which can be used to investigate and calibrate so-called "friction coefficient sensors". These measuring facilities are used to measure the prestressing force and the tightening torque, resp. the friction torque of screws. These measurements are aimed at optimizing screw joints. The measuring facility described here is part of a force standard machine (fsm). In addition to the force which this system can realize with a very small measurement uncertainty of 0.002 % (<em>k</em> = 2) (in the measuring range from 20 kN to 1 MN), it can also generate an extremely precise torque (objective: better than 0.005 % at <em>k</em> = 2) in the range from 20 N·m to 2 kN·m.