Logo PTB

Scientific news from division 1

Due to the redefinition of the kilogram and due to the new possibilities this offers to disseminate the unit kilogram for a practice-oriented and stable traceability chain, the demand of national metrological institutes, calibration laboratories and balance manufacturers for silicon spheres is very high. In this context, the "Si-kg" transfer project, together with the participating companies, has...

[ more ]

When carrying out fatigue tests, the connected signal conditioning electronics must also be calibrated. One way of doing such a calibration is described in the international standard ISO 4965-2. The first part of the standard deals with the associated test systems. At PTB, a calibration of such a measuring amplifier has now been performed for the first time for a customer. The calibration...

[ more ]

The sound emission of technical devices, machinery and equipment has to be declared for purposes of environmental protection, occupational health and consumer information. An upper limit for the sound emission is legally binding for some machines used outdoors. The descriptor for sound emission is the sound power level, which is measured by internationally harmonised methods. A disadvantage of...

[ more ]

Within the scope of the EU joint project titled Ears II (EMPIR project No. 15HLT03), hearing tests were planned at PTB in order to investigate how humans perceive infrasound (frequencies f below 20 Hz) combined with sound in the "conventional" acoustic frequency range (i.e."audible sound" in the frequency range 20 Hz ≤ f ≤ 20 kHz). The first step consisted in developing a sound source system able...

[ more ]

PTB is developing a measurement procedure to determine airborne ultrasound exposure at the workplace and is hereby pursuing an open-science strategy in order to make the research data and results freely available to the public. In this way, the development and testing of this procedure, which was designed for occupational safety and health, becomes transparent and comprehensible. Furthermore, it...

[ more ]

The volume of silicon spheres with a mass of 1 kg could previously be measured by means of hydrostatic weighing with an uncertainty of 0.8 mm³ (k = 2). Using new and more stable thermistors to determine the temperature distribution in the measuring liquid of the fundamental weighing apparatus, a hydrostatic volume determination with an uncertainty of 0.35 mm³ (k = 2) will be possible in the...

[ more ]

For the first time, torque measurement in nacelle test benches has been traced to the national standard. Common torque calibration standards only provide methods for static torque calibration. However, for torque measurement in nacelle test benches, calibration at varying rotational speeds is required. The findings and research will contribute to a reliable efficiency determination.

[ more ]