Scientific news from division 1

In the context of the European Metrology Research Programme (EMRP), the Joint Research Project IND09 focuses on the dynamic measurement of mechanical quantities (force, pressure, torque). For the determination of model parameters of a dynamic torque measuring device, the mass moment of inertia and torsional stiffness properties are to be determined. For this purpose two measurement set-ups were...

The current state-of-the-art approach to provide traceability of flow standard facilities – based on the SI units mass, density, temperature and time – relies, in practice, on applying purely static traceability chains of the measurands which are involved in fluid flow measurement. Even a mere model-based theoretical consideration clearly shows that dynamic influences or disturbing effects occur....

For the first time printed scattering particles have been used for the calibration of Laser Doppler Anemometers (LDA). They are to contribute to a better reproducibility of calibration results of various LDA systems.

Wind potential analyses, used to assess the cost effectiveness of wind farms, are currently based on the measurement of wind velocity by means of cup anemometers mounted on meteorological masts. As an alternative to these expensive and difficult to erect met masts, a doppler lidar system for traceable, ground-based laser-optic wind velocity measurements has been developed at PTB.

A 2-day workshop was held in Heidelberg, Germany on 14th and 15th of June 2012 on the topic of exposure and dose for therapeutic ultrasound: 37 experts from 26 institutions in 9 countries participated. The workshop was the first stage of an international European Metrology Research Programme (EMRP) project "Dosimetry for Ultrasound Therapy" (www.DUTy-project.eu).

It could be shown by a comprehensive measurement program and additional computer simulations that the installation noise levels according to the new standard DIN EN ISO 10052 are larger by 2 dB than the levels determined in accordance with the old standard DIN 52219.

For PTB's reference facility for vehicle speeds, which is based on piezoelectric pressure sensors, the measurement uncertainty budget was verified by comparisons with a high-quality GPS inertial system.

The numerical simulation of a non-linear parabolic equation (the KZK equation) can be favorably applied to the determination of extremely high pressure amplitudes of modern therapeutic ultrasound devices and complement the experimental hydrophone measurement technique.

In Germany accredited calibration laboratories in the wind industry predominantly use Prandtl tubes indicated as Pitot static tubes as reference standards for the calibration of far over 10.000 anemometers per year. Comparison measurements with Laser Doppler-Anemometers as transfer standards have shown that the traceability of air speed measurements given by Prandtl tubes can be realized in the...

Precision torque transducers based on strain gauges can, as far as they are not hermetically enclosed, be influenced by the humidity contained in the ambient air. Measuring the humidity coefficient which describes this property has, so far, only been possible by means of very tedious procedures. Hence, accredited calibration laboratories were, for financial reasons, not able to measure this...

Im Rahmen des Leistungsangebots der PTB können Kalibrierungen von kritisch betriebenen Venturidüsen mit inerten Gasen und Gasgemischen im Druckbereich von p = 0,8 bar bis 6 bar und bis zu einem Durchfluss von Q = 10 m³/h im Normzustand standardmäßig durchgeführt werden.

Nine accredited calibration laboratories will participate in the first interlaboratory comparison organized within the scope of responsibility of the Deutsche Akkreditierungsstelle GmbH (German Accreditation Body - DAkkS) to determine the magnetic properties of mass standards. PTB assumes the role as pilot laboratory regarding the preparation, coordination and evaluation of the comparison...

A series of comparison measurements between the DAkkS-accredited calibration laboratories for the unit of acceleration and the PTB confirms the high quality level of the German traceability system in this field. The excellent results have been published internationally.

After a complex planning phase, the implementation of a machine allowing both longitudinal force and torque to be generated simultaneously is entering into its final phase. The measurement facility extends PTB's measuring capabilities for the calibration of so-called "multi-component sensors".

Auf der Grundlage eines umfangreichen Messprogramms und unter Einbeziehung moderner laseroptischer Verfahren zur Diagnose der Strömungsbedingungen vor und im Inneren der Zähler konnte der Nachweis erbracht werden, dass Wasser- und Wärmezähler auch in Messkapselausführung den messtechnischen Anforderungen der Europäischen Messgeräterichtlinie MID an Wasserzähler entsprechen.

In cooperation with the Römisch-Germanisches Zentralmuseum (RGZM – Romano-Germanic Central Museum) in Neuwied/Germany, a procedure to reproduce ballistic experiments with stone-age spearheads was developed within the scope of a DFG project. As the original artefacts from the Stone Age differed individually from each other and as a possible destruction of the spearheads had to be avoided,...

When video motorcycles are used to measure the speed of vehicles, the tilted-position effect occurs. This tilted-position effect is a reduction in the rolling circumference which is dependent on the tilted position. To rule out disadvantages for motorcyclists, limitations in the application are required. PTB has now carried out detailed experiments in relation with the tilted-position effect and...

Determining the threshold of hearing with pure-tone stimuli is the most widely used and most fundamental audiometric procedure. As for all measurement procedures, correct calibration plays a decisive role for the reliability of the results obtained. In the new version of EN ISO 8253-1 (Acoustics – Audiometric test methods – Part 1: Basic pure-tone air and bone conduction threshold audiometry),...

On PTB's initiative, the treatment of measurement uncertainties in the standardization of electroacoustic devices is soon to become understandable for everyone.

So far, video-based measurement of the speed and distance of vehicles has only been possible on practically straight and flat road sections. However, accidents more frequently occur on hilly motorway sections with tight bends and cross slopes. Since the type approval for the VIDIT traffic-monitoring system (VKS) has been extended, the speed and distance can now be measured in exactly such...

Der graue Star (Katarakt) zählt zu den häufigsten Erkrankungen im Alter und ist durch eine Trübung der Augenlinse gekennzeichnet. Im Fall einer deutlichen Absenkung der Sehschärfe wird die getrübte Augenlinse mittels Ultraschall entfernt (Phakoemulsifikation) und durch eine Kunststofflinse ersetzt. Als Komplikationen während der Operation können hierbei thermische Schäden auftreten. An der PTB...

The reference hearing thresholds for a commercially available otoacoustic emission probe were determined. This will enable the application of this probe also in subjective hearing tests.

Vom 1. bis 5. Oktober 2012 fanden die 14. Konferenz der Internationalen Organisation für das gesetzliche Messwesen (OIML) und die 47. Sitzung des Internationalen Komitees für das gesetzliche Messwesen (CIML) in Bukarest, Rumänien, statt. Insgesamt nahmen knapp 170 Delegierte und Beobachter aus 48 (von 57) Mitgliedstaaten, 12 korrespondierenden Mitgliedstaaten sowie mehreren internationalen...

During the 8th session of the WGFF in June 2012 in Colorado Springs/USA, specific proposals for implementation of actual documents of CIPM and ILAC regarding the measurement uncertainty given in CMC entries and in calibration certificates have been discussed and summarized in a guideline for the field of fluid flow measurement.

Die präzise Messung von Kräften ist für viele Produktionsprozesse sowie in der Forschung und Entwicklung eine Voraussetzung für beste Arbeitsergebnisse. Neben der Qualität der Kraftmessgeräte ist die exakte Definition der Krafteinheit Newton in den nationalem Metrologieinstituten von großer Bedeutung. Insbesondere aufstrebende Länder wie Indien bauen in den letzten Jahren dazu neue Anlagen auf,...

On 01 June 2012, the European research project "Developing a practical means of disseminating the new kilogram" (EMRP/SIB05) started with the participation of fourteen partners from thirteen countries.

High-intensity therapeutic ultrasound (HITU) is a non-invasive and non-ionizing therapy method in which locally very high ultrasonic intensities (> 10 kW/cm²) can be produced in the body by focusing an ultrasonic field. These high intensities then induce, for example, necrotization and thus the destruction of tumor tissue. Although the number of applications is constantly increasing, there are...