In many fields of industry – such as for example air-conditioning, environmental technology, meteorology, aviation or wind energy – information about flow velocity is of substantial importance. Measurement devices for detecting the measurand flow velocity, for example vane anemometers, are usually calibrated in wind tunnels.
PTB operates two wind tunnels for the realization and dissemination...

In dosimetry for radiation protection in pulsed fields of ionising radiation, problems occur when the use of electronic radiation protection dosemeters is prescribed. As a reaction, PTB has set up the world's first facility for the generation of pulsed X-ray radiation in which the physical parameters of the radiation pulse can be adjusted. This pulsed X-ray facility was developed in close...

One of the most important components of the Hydrodynamic Test Field (HTF) – and relevant for its functioning – is the flow diverter. Extensive experimental investigations of the timing error of the corresponding diverting processes and an exact, model-based functional analysis of these processes have greatly contributed to ensuring and quantitatively improving the Hydrodynamic Test Field's...

The petroleum test rig is an integral part of PTB's system of primary standards in the field of volume and flowrate measurement; it works specifically with fluids other than water. The extensions which have been carried out considerably improve the operation of the test rig and now enable us to investigate the transferability of measurement results which have been obtained using the...

An objective hearing test with otoacoustic emissions (OAE) provides information on the inner ear sensory cell performance (cochlear function), even if no cooperation of the subject (e.g. babies) can be expected. OAEs are evoked as a response to an acoustic stimulus and indicate a healthy inner ear. Usually, the stimuli are presented in the ear canal with miniature loudspeakers. An alternative...

Using a modified setup of the radiation force balance, the primary standard for the realization of the unit W in ultrasound, the output power of High Intensity Therapeutic Ultrasound (HITU) transducers could be measured reliably. In the process, a strongly focusing high power transducer was excited with electrical powers up to 500 W.

It is common practice to use sinusoidal sound signals as an excitation signal to reach the low measurement uncertainties required for the testing of the directional response pattern of sound level meters and for the calibration of measuring microphones. By using broadband signals, it has now become possible to reduce the time needed for a measurement, to considerably increase the spectral...

In the past few years, the development of highly sensitive atomic magnetometers has made considerable progress. At the National Institute of Standards and Technology/USA (NIST), optical micromagnetometers ...

In X-ray mammography benign breast tumors are often classified as highly suspicious lesions. Therefore, new or additional imaging techniques are required which offer an improved differentiation ...

New approaches for meter systems do not anymore only use information and communication technologies as an accepted addition of meters, but its functionality bases on the systematic exploitation of the communication infrastructure. This development already ranges to meters used ...

The breathtaking development of nanotechnology requires the design and control of components with smaller and smaller details. In particular, the fabrication of up-to-date computer chips and storage devices by lithographic manufacturing processes ...

Magnetic nanoparticles are applied today routinely as a contrast agent for magnetic resonance imaging. In addition to medical diagnostics ...

Many important equations of classical and modern physics are linear partial differential equations which describe quantities which continuously depend on space and time. Since 1990, mathematic-theoretic research has increasingly turned its attention to non-linear evolution equations. An important class here are reaction-diffusion equations which have important applications in biological and...

In the framework of an EU funded project a simulator to test non-invasive sphygmomanometer was developed. Such simulators are mainly used for research. Although the EU simulator is able to test also sphygmomanometers with new functionalities, the recording unit for the test signals from humans was limited in its capabilities. To overcome this bottleneck, PTB working group 8.12 has developed a new...

Während der Vorbereitungsmessungen für die anstehende internationale Vergleichsmessung im Bereich der Darstellung der Messgröße Beschleunigung wurden signifikante Differenzen zwischen den Ergebnissen von Kalibrierungen, die auf verschiedenen Schwingerregern gemessen worden waren, gefunden. Die nähere Untersuchung dieses Phänomens führte zur Entdeckung eines bislang nicht beobachteten...

When a dilute gas is cooled close to absolute zero the motion of the gas particles have to be described by quantum mechanics: The particles start to behave as waves. If the de-Broglie wavelength reaches the mean inter particle distance, a phase transition to a new state can occur: Bosonic particles accumulate in the ground state of the system forming a Bose-Einstein condensate. Bose-Einstein...

Die Funktion von pulsgetriebenen Josephson-Schaltungen für Wechselspannungen wird maßgeblich von ihrem Mikrowellenverhalten bestimmt. Messungen von Strom-Spannungs-Kennlinien als Funktion der Mikrowellenfrequenz liefern nun Hinweise, warum bei einigen Schaltungen nur eine mangelhafte Oberwellenunterdrückung zu beobachten ist.