| News from the Annual Report 2005 |
• Fundamentals of metrology |
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The influence of structure-borne modes on the sound insulation
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It was shown by scaled model measurements that different frequencies of the structure-borne sound modes of a test specimen lead to an uncertainty of about 2 dB in the measured sound reduction index at low frequencies.
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The hydrodynamic test field - Utilisation for the improvement in the characterisation of measuring devices
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With a high temperature stability and the possibility of adjusting the temperature of the test fluid over a wide range, the hydrodynamic test field, as a high-accuracy water flow calibration facility, offers new qualitative possibilities of more precise calibrations of measuring devices and reduces the measurement uncertainty during traceability and comparison measurements.
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Laserinterferometric measurement of motion disturbances of acceleration exciters and consequently adapted calibration methods
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The resonances and disturbing motions of acceleration exciters have been investigated with the help of a 3D-Laservibrometer and a Scanning-Laservibrometer. As a consequence the influence of these disturbances on the results of primary calibration of accelerometers has been reduced largely.
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PTB obtains new prototype balance
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After having been used for more than 17 years, the comparator balance of PTB used so far as prototype balance is replaced by a high-resolution 1 kg vacuum mass comparator of the latest generation.
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| • Metrology for economy |
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The new assembled flow rate comparator for flow rates within 0.02 to 4 m³/h; patent pending
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Measurement of the flanking sound reduction in normal test facilities
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Most laboratories don't possess special test facilities for the measurement of the flanking sound reduction. Those laboratories, as a remedy, install the test object into normal test facilities. PTB examined this procedure.
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Quantitative determination of the cleaning effect of ultrasound baths
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The recording of spectral sound field parameters directly in the cleaning bath allows the efficiency of ultrasound-based cleaning processes to be determined and optimized.
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A new set-up for type approval testing and calibration of sound calibrators
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A new set-up allows the automatisation of tests for the type approval and the calibration of sound calibrators.
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| • Metrology for society |
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Portable power standard for the traceability of measuring devices for ultrasonic physiotherapy equipment
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A portable power standard for the traceability of measuring devices for ultrasonic physiotherapy equipment has successfully been developed and tested in an international cooperation under EU funding.
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Large discrepancies in auralisation results
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A comparison of different auralisation results obtained with various room acoustic simulation tools led to large differences which can be attributed to the use of different dummy head microphones as well as to differences in the ray tracing methods and convolution algorithms.
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In-situ testing of domestic water meters will soon be possible
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First positive results of a joint research project of PTB and verification authorities show that in-situ water meter testing is technically feasible and serve as a basis for a corresponding extension of the existing provisions for in-service testing.
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Impulse force flowmeter
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Due to a novel flowmeter for which a patent is pending, it is possible to measure the mass flow of a fluid independent of its material properties, by means of an impulse force measurement.
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New temperature chamber for the testing of load cells up to 200 t
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A novel temperature chamber in combination with a deadweight force standard machine (FSM) allows the testing and certification of load cells with nominal loads up to 200 t by the Physikalisch-Technische Bundesanstalt (PTB). This facility is unique in Europe; for the first time, it offers manufacturers and customers the possibility of certifying load cells with very high nominal loads as used in the heavy industry for instance.
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Acoustic perception of an approaching ambulance siren
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It was found out that inside a car there is often hardly a warning effect of the siren of an approaching ambulance or no effect at all. It has to be considered that the sound pressure levels very much depend on the car. Especially in new and expensive cars great importance is attached to external sound insulation which further reduces the audibility of external warning signals which further reduces the audibility of external warning signals.
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| • International affairs |
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First CIPM Key comparisons in the world in the field of torque measurement
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In May 2005, the first international key comparisons in the field of torque realization and torque measurement were initiated. Under the umbrella of the CIPM (Comité International des Poids et Mesures/International Committee for Weights and Measures), the best measuring facilities in the world are compared among one another to find out how well they agree and whether the measurement uncertainties specified for these facilities are plausible.
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Revision of world-wide applied standard R76 for non-automatic weighing instruments far progressed
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The works on the revision of the world-wide applied recommendation "R76" of the "Organisation International de Métrologie Légale" (OIML) for non-automatic weighing instruments have already progressed far. The presumably last draft is finished in September of this year and is distributed to the members of the OIML committee for non-automatic weighing instruments for a vote.
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Key comparison for high-pressure natural gas successfully completed
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In spring 2005, a CIPM Key Comparison for high-pressure natural gas was successfully completed. It turned out that only three of all high-pressure test facilities in the world were prepared and technically in a position to participate. The result of this CIPM comparison is that the reference value is identical with the harmonized European natural gas cubic metre which has been made available by PTB, NMI-VSL and LNE since May 2004.
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| Back to the Latest scientific news |
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