| News from the Annual Report 2009 |
| • Fundamentals of metrology |
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Measuring set-up for the primary phase calibration of laser Doppler vibrometers developed
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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) also supplies a Michelson interferometer which is operated in quadrature and serves as a reference.
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Improved Operability of the Hydrodynamic Test Field
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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been in operation for more than ten years, the entire IT hardware and software of the hydrodynamic test field has been replaced by new, state-of-the-art computer hardware and the corresponding system and user software.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.
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In-situ Calibration of Fluid Meters by means of Novel Injection Method
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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 makes it possible to calibrate quantity and flow meters under operating conditions at the place of installation by means of a static standard (based on the exact determination of the mass or the volume).
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New Calibration of the White-Spirit-Operated Mineral Oil Test Rig
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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 the white-spirit-operated mineral oil test rig has been equipped with a magnetostrictive height-measurement system and has been newly calibrated.
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Lothar Cremer Prize Winner 2009: Volker Wittstock
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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.
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Robust signal statistics for the realization of the unit of sound pressure
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By using advanced signal statistics procedures, the measurement time required for the pressure reciprocity calibration of laboratory standard microphones was reduced.
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Measuring the photodetector frequency response by a heterodyne system with difference-frequency servo control
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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.
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| • Metrology for economy |
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Reconstruction of PTB wind tunnel with 320 mm nozzle completed
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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.
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New silicon load cells
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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.
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Set-ups of measuring devices to determine the deformation of force transducers
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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.
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A compact method for the determination of impact sound reduction
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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.
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Torque references cross-loaded
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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 influences of these unequal conditions were investigated for typical examplary situations with the aid of special devices in order to give recommendations for the uncertainty calculation in the calibration laboratories concerned.
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Realization of gas volume flows with considerably reduced measurement uncertainty
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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.
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| • Metrology for society |
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Useful CHIRPs - Newborn Hearing Screening supported by latest PTB research
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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 quantities.
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Type approval of a video-based system for determining speed differences between vehicles
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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 is now possible to determine the differential speed of two vehicles during overtaking, so that such hazardous passing manoeuvres can now be punished.
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A more simple acoustic output beam characterization of diagnostic ultrasound equipment using thermal intensity sensors
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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.
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Sound insulation screens successfully tested in orchestras
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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 measurements could now also be confirmed by measurements performed during an orchestra rehearsal at the Städtische Bühnen Münster/Westphalia.
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Tuning of Weighing Instruments by Means of Upgrading Modules
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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 functions in the software of the module - it is, in addition, possible to upgrade existing weighing instruments into price-labelling weighing instruments.
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New laser scanning procedure for large storage tanks presented
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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 measurement of large storage tanks, met with unexpectedly great response.
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Calibration of ergometer test facilities now carried out by Working Group "Torque Realization"
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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".
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New Dictionary of Weighing Terms
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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).
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| • International affairs |
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All over the world – weighing instruments made in Germany
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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 Légale), ensure that the weighing instruments tested by PTB can be approved in numerous countries in the world.
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Chinese-European Gas-Metrology Conference
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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.
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Application of the modular concept with weighing instruments
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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 latest issue of OIML recommendation R76-1 (Metrological aspects of nonautomatic weighing instruments) dated 2006.
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Revision of OIML Recommendation R50 (belt weigher) soon to be finished
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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.
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OIML News
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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.
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News from past Annual Reports |
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2008 |
2007 |
2006 |
2005 |
2004 |
2003 |
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