Scientific news from division 1

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...

In the Working Group "Realization of Acceleration", a measuring set-up was developed within the scope of a diploma thesis at the University of Applied Sciences Braunschweig/Wolfenbüttel for the primary determination of the phase retardation of laser Doppler vibrometers (LDVs). To achieve measurement uncertainties as small as possible, the laser beam of the test object (LDV measuring beam)...

PTB's white-spirit-operated mineral oil test rig is used to test and calibrate quantity and flow meters which are dedicated to the measurement of fluids other than water. Its operation modus (now also with direct pumping and "flying" start/stop operation) as well as its controlling are presently being radically extended. Within the scope of this extension, also one of the volumetric standards of...

Quantity and flow meters are tested and calibrated under reference conditions by means of stationary measurement equipment. This becomes a problem when the measurement conditions in the industrial application differ from these conditions, so that the behaviour of a flow meter changes and the measurement results are, thus, biased. Such problems can be avoided by using a patented method which...

After having been in operation for more than ten years, the entire IT hardware and software of the hydrodynamic test field has been replaced by new, state-of-the-art computer hardware and the corresponding system and user software. In this way, the reliability, functionality and operability of the plant could be considerably improved.

On 24.3.2009 Volker Wittstock was awarded the Lothar Cremer Prize of the Deutsche Gesellschaft für Akustik (German Acoustical Society) on the occasion of the annual conference on acoustics in Rotterdam. The DEGA presents this prize once a year for outstanding work by young scientists.

By using advanced signal statistics procedures, the measurement time required for the pressure reciprocity calibration of laboratory standard microphones was reduced.

A technique for the calibration of photodiodes using standard and cost-effective optical and electronic elements is presented which allows the determination of the photodetector’s frequency response under conditions used in ultrasonic applications.

PTB´s Eiffel type wind tunnel with a 320 mm nozzle diameter was originally driven by the blower of the gas meter test rig. Now the wind tunnel has been reconstructed into a self-sustaining closed-loop Göttinger type wind tunnel, which can optionally be operated with an open or a closed measuring section.

Durch den Einbau von Ultraschallgaszählern als zusätzliche Gebrauchsnormale zu den bereits existierenden Turbinenradgaszählern sowie zum kontinuierlichen Vergleich mit Gasqualitätsdaten wurde in Kooperation mit der PTB die Qualitätssicherung und Langzeitstabilität des Hochdruck-Gaszählerprüfstandes pigsar^TM der E.ON Ruhrgas weiter verbessert.

At PTB, the technology of conventional strain gauge load cells has been further developed, also for high-precision weighing. The new load cell made of monocrystalline silicon (instead of metal) with sputtered-on (instead of glued) thinfilm strain gauges shows a significantly improved time and hysteresis behaviour, as well as a better reproducibility.

On static and dynamic force measuring devices, set-ups have been realised and investigated which allow the deformation of force transducers under load to be measured by means of a differential laser vibrometer. Especially in the range of dynamic measurements, it is often necessary to know the deformation path in addition to the force.

To calibrate torque transducers by means of the comparison procedure, so-called reference transducers are needed which furnish traceable torque reference values. These reference transducers, in turn, are calibrated in high-grade facilities in which the reference transducer are subjected to other – normally smaller - cross forces and bending moments than in the comparison procedure. The...

The effort to determine impact sound reduction is high due to the use of a building acoustic test facility consisting of two rooms of about 50 m³ each. A compact measurement method was now developed at PTB where the complete two-room configuration is replaced by a desk-sized setup.

As to the flow measurement of gaseous media, the European metrology organisation EURAMET has set itself the target to reduce the on-site measurement uncertainty by factor 5. With a novel fundamental apparatus, PTB has now significantly approached this target.

In cooperation of scientists of the department Mechanics and Acoustics with Mettler-Toledo AG the Springer publishing house has released the ”Dictionary of Weighing Terms” (ISBN 978-3-642-02013-1).

Everyone has been annoyed by a traffic situation with a slow-moving lorry blocking the overtaking lane. Such overtaking manoeuvres can cause considerable delays and endanger other road users; when two lorries are involved, it results in a "lorry duel" (the Germans call it an "elephant race"). By extending the type approval which was granted to the VIDIT company's traffic-monitoring system, it...

Demand for solid precision instruments for objective audiometry rose sharply after the German government's decision to include newborn hearing screening in the catalogue of public health insurances in 2009. Recently, PTB's assessment of the hearing thresholds of high-efficiency "Chirp" test signals has enabled reliable calibration of hearing screening equipment and fostered the sale of large...

Thermal sensors developed at PTB can be favourably applied to the measurement of intensity profiles of modern diagnostic ultrasound devices and complement the conventional hydrophone measurement technique.

After the implementation of the new EU Directive 2003/10/EG regarding protection against noise at the work place, a sound insulation screen for orchestra musicians has been developed in a joint project of WG 1.72 "Noise Measuring Technology", the Städtische Bühnen Münster und the Accident Insurance North-Rhine Westphalia. The sound reduction values already determined in laboratory...

In the field of weighing technology, the first certificate for a special module for weighing instruments has been issued. This module realizes functions which make it possible to convert connected, simple weighing instruments which have no price-computing function into weighing instruments having a price-computing function. By connecting a label printer - in combination with suitable...

The International Workshop "Calibration of storage tanks by optical scanning", which took place in Hamburg on June 17 and 18, 2009 and constituted, for the present, the conclusion of a very successful cooperation between PTB, the Verification Authority North and the Trimble Holdings GmbH (formerly CALLIDUS precision systems GmbH) in the development of a novel procedure for the laser-optical...

According to the Medical Devices Act, foot pedal ergometers are considered as "medical devices with a measurement function". The rotational power provided by the patient is measured as a product of momentary rotation speed and acting torque. The standard to which all calibrated ergometers are finally traced back is now operated at PTB by the Working Group "Torque Realization".

Every third weighing instrument worldwide is "Made in Germany". The large market share of Germany's weighing instrument industry reflects the good reputation of its products – they are viewed as precise and dependable. The Physikalisch-Technische Bundesanstalt (PTB) has also contributed to this success. Its certificates awarded according to OIML (Organisation Internationale de Métrologie...

Over 130 technical experts in gas volume measurement technology and legal metrology from China and Europe had the opportunity to exchange ideas on 3rd and 4th November 2008 in Beijing about the current developments in the gas sector.

In the second issue of the OIML-Bulletin of 2009 (OIML = Organisation Internationale de Métrologie Légale) an article about the application of the modular concept has been published by employees of Department 1. The motivation to do so were difficulties on the part of the BIML as well as on the part of some OIML members in metrological interpretation of the modular concept presented in the...

At present the OIML Recommendation R50 for belt weigher is being revised and adopted to current technical developments. Amongst others it is the objective to treat belt weighers with regard to EMC (electromagnetic compatibility) and testing against software aspects in the same way as other types of weighing instruments.

At the end of October 2008, the 13th International Conference on Legal Metrology was held in Sydney, Australia. A total of 127 participants from 41 member countries and eight corresponding member countries attended this Conference of the International Organization of Legal Metrology (OIML), held every four years.