Erstmals wurde ein modellbasiertes Konzept zur Darstellung des Momentandurchflusses einer strömenden Flüssigkeit entwickelt und mit ersten Untersuchungsergebnissen auf dem Hydrodynamischen Prüffeld belegt. Im Gegensatz zur sonst üblichen Durchflussmessung, bei der der mittlere Durchfluss über den Gesamtzeitraum einer Messung ermittelt wird, ermöglicht das neue, dynamische Verfahren erstmals die...

The 20 kN·m torque standard machine of PTB ranks among the best facilities of its kind in the world. To ensure this leading position also in the future, investigations and comparisons are performed at regular intervals. In the last few years, a small asymmetry in the arm lengths of the lever (the right arm was too short by approx. 10 µm, the left too long by approx. the same amount) has been...

When investigating building acoustical problems on downscaled models, detailed data on the mechanical properties of the used materials were needed for experimental and numerical purposes. To determine the properties such as Young's modulus and material damping a number of established measurement methods exist, partially as normative references. Unfortunately, these measurement methods usually...

The stability of the 1 kg vacuum mass comparator Sartorius CCL 1007 could be improved considerably for mass determinations in air by an additional thermal insulation. Mass determinations in air are now possible with standard deviations of less than 0.1 µg. Comparable results were achieved up to now only under vacuum conditions.

As commissoned by Hella Fahrzeugkomponenten GmbH, Bremen, measurements of the ultrasound propagation speed in engine oils as a function of temperature in the range from 8°C to 153°C were performed. The data obtained are important for the estimation of the uncertainty of the ultrasound based oil-filling level measurement in car engines recently developed.

Since 1999 exists a German-Japanese agreement on the mutual recognition of the test results of non-automatic weighing instruments. The rapid metrological progress of the past few years in the field of weighing technology has made a revision necessary. For this reason, a comprehensive extension of the agreement has been signed on June 5, 2007 by PTB and the National Metrology Institute of...

At the ion accumulation experiment the mass of accumulated ions and thereby the measurement uncertainty is governed by the value of the ion current at the collector. In order to achieve the maximal ion current with the existing apparatus simulations and measurements were performed for optimizing the parameters gas pressure and extraction voltage at the ion source as well as the transmission...

The receiving range of a sound field measurement in a bubble cloud was determined to better employ such measurements for an optimum use of cavitation.

In June, the project "Model-based calibration of accelerometers", which is supported by the Federal Ministry of Economics and Technology (BMWi) and carried out by PTB together with SPEKTRA Schwingungstechnik und Akustik GmbH Dresden ("SPEKTRA Vibration and Acoustic Systems Engineering"), will be launched. The project is promoted within the scope of the Measurement Standards Testing and...

By the free-field reciprocity calibration of quarter-inch measuring microphones, the basis for the realization of the sound pressure unit has been created for frequencies up to 160 kHz.

With the new Gravity Information System, a novel information platform is presented on the web pages of PTB. On this platform, users from metrology can inform themselves about the local intensity of the earth’s field of gravity, related to the place of use. A four-stage gravity data model, mainly composed of freely available secondary (i.e. derived) gravitational field quantities, serves as a...

Problems in building acoustics can be investigated excellently on small, downscaled models. They are more flexible, require less time and effort and are cheaper than the usual measurements carried out in large and standardized test facilities, and they are also more reliable and realistic than most computer simulations. A downscaled model of a building-acoustics wall test facility has been...

The PTB makes its accelerator available for use by groups of external researchers in the scope of the EU-supported Integrated Infrastructure Initiative EFNUDAT.

A workshop on "Source Preparation in Radionuclide Metrology" was held at the PTB in the framework of the Virtual European Radionuclide Metrology Institute (VERMI). The event gave participants from the NPL, LNE-LNHB, IRMM and PTB the opportunity to exchange their experience in theory and in practice.

It was shown by scaled model measurements that in test facilities, homogeneous building elements have a larger sound reduction than in real buildings. This is a broadband effect which decreases with increasing frequencies and amounts up to 5 dB at low frequencies.

With the coming into force of the new Measuring Instruments Directive 2004/22/EC (MID) on 31 March 2004, Working Group 1.13 of PTB set out to prepare itself for the new development - thus already long before the planned Europe-wide implementation of this directive by 30 October 2006. At the beginning of 2005, information letters were sent out to approx. 100 manufacturers of weighing...

Within the scope of a biennial third-party project, the thoron progeny chamber was fully equipped.

Within the scope of a scientific cooperation between Sartorius AG and PTB a 1 kg vacuum mass comparator developed by Sartorius AG in cooperation with the Bureau International des Poids et Mesures (BIPM) and the Technische Universität Ilmenau was installed at PTB. As a result of first measurements standard deviations of < 0.2 µg in air and < 0.1 µg in vacuum could be achieved for the mass...

The activities of PTB in the field of fusion research will continue after a collaboration contract between PTB and the Max-Planck-Institut für Plasmaphysik (IPP) in Garching and Greifswald has been signed recently.

In the field of luggage control a time-resolved imaging system for γs and fast-neutrons was developed and used for first experiments on gamma radiography at Jena University’s terawatt laser.