PTB, Germany

To evaluate the degree of equivalence of the national primary measurement procedures for pH, the first key comparison for this quantity was recently carried out by the CCQM on two phosphate buffer solutions. These experiments were piloted by the PTB Germany and involved another ten metrology institutes. A first evaluation of the results obtained shows that the majority of the results agree within the uncertainty stated by the participants. The draft B for this comparison will be available soon. 

British Approvals Service for Electrical Equipment in Flammable Atmospheres (BASEEEA) and Physikalische-Technische Bimdesanstalt (PTB), Germany, which, along with other European approvals bodies, provides certification to the European Committee for Electrotechnical Standardization (CENELEC) standards... 

As a standard characterization the mean GTE (0/50) value in the temperature interval between 0 to 50 °G is measured in pushrod dilatometers made of titanium silicate (ULE 7971). An inductive transducer (LVDT) registers the motion of the pushrod with a resolution of 5 nm. The electromechanical sensitivity of the LVDT is calibrated with a Michelson interferometer. The expansivity of the dilatometer itself is determined by measuring standard materials for calibration. The standard materials (ULE , fused silica) have been measured especially for Schott in vacuum interferometers by the National Standardization Institutes PTB (Germany) and NPL (GB). 

In Germany, deflagration and detonation flame arresters are tested and approved by the German Federal Physical-Technical Institnte (PTB) in Brannschweig and the German Federal Institnte for Material Research and Testing (BAM) in Berlin. However, once the new Enropean Committee for Standardization (CEN) standard is approved, it will supersede the PTB and BAM procedures. 

Schampel and Steen (1975) describe experimental equipment and tests carried out at the Physikalisch-Technische Bundesanstalt (PTB) in Germany on high velocity vent valves. Also, conditions for a sufficient air entrainment and dilution of the vented flammable vapors are discussed. 

In Germany flame arresters are tested in accordance with the TRbE standard (Technical Rules for Inflammable Liquids) and approved by the German Eederal Physical-Technical Institute (PTB) and the German Eed-eral Institute for Material Research and Testing (BAM). However, this standard will be superseded by the new CEN standard. 

The ITS is an artifact scale, designed to relate temperature measurements made with practicable instruments as closely as possible to the thermodynamic scale. The scale is established and controlled by the International Committee of Weights and Measures (BIPM) through its Consultative Committee on Thermometry, which was established in 1937. The BIPM itself is established to maintain and implement the Treaty of the Meter, to which most nations of the wodd subscribe thus the ITS has not only scientific but legal status in most nations. Within nations, the Temperature Scale is maintained by national standards establishments, eg, in the United States the National Institute for Standards and Technology (NIST), in England the National Physical Laboratory (NPL), and in Germany the Physikalisch-Technische Bundesanstalt (PTB). 

Fig. 2 The traceability system for gas analysis in Germany is composed of three chains, one for the legally regulated area via verification authorities, one for the non-regulated area via DKD-accredited calibration laboratories and one for the air pollution monitoring networks. Here the national reference level consists of PTB, BAM and UBA (cf. text) which share the responsibility for the national measurement standards needed, according to agreements with PTB...

Fig. 1 Traceability system for the determination of the most important diagnostic markers in human body fluids in Germany. The clinical reference laboratories at the intermediate level providing calibration means to the routine medical laboratories are accredited as calibration laboratories in the framework of the German Calibration Service (DKD) and are firmly linked to the national metrology institute, PTB, by comparison measurements carried out on actual laboratory samples. Accreditation is in part required by the Federal Physicians Council (BAK) or is voluntary. The traceability system is still under development...

Abstract Current developments in Germany for establishing a traceability system for chemical measurements are reported. The focus is on a dissemination mechanism which employs chemical calibration laboratories accredited within the framework of the German Calibration Service (DKD) and acting as multipliers between the national standards level and the user level by providing the user with calibration means which are traceable to the SI via national standards. At the national standards level, a network of high-level chemistry institutes coordinated by the national metrology institute, PTB, provides the primary references for chemical measurements. 

It is worth mentioning that the development of complex matrix reference materials such as PAH in soil has been successfully carried out under the collaboration program with PTB/BAM in Germany, by exchanging experts and use of complementary measurement capabilities [10]. 

In Germany since 2001 BAM and PTB have provided a service regarding national standards for dissemination of traceability. The service elucidates the endpoints of traceability of results of chemical measurements in Germany and is a German contribution to an international system aimed at mutual recognition of national standards. 

Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany... 

Heidelberg, E., Ignition of Explosive Atmospheres by Static Electricity, PTB (Physikalisch-Technische Bundesanstalt), Mitteilungen, Germany, 1970. 

The first frequency measurement of the 15 — 25 resonance made use of a transportable ClU-stabilized HeNe infrared frequency standard at 88 THz [24], built at the Institute of Laser Physics in Novosibirsk/Russia. For calibration it was transported repeatedly to the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig/Germany where it could be compared with a Cs atomic clock using the PTB frequency chain [25]. 

As shown in Fig. 7 we compared the frequency of the cesium Di line at 895 nm with the 4th harmonic of the methane stabilized He-Ne laser operating at 3.4 pm (/ = 88 THz). The laser that creates the frequency comb, the fourth harmonic generation and the HeNe laser are identical with the systems shown in Fig. 4. However, the HeNe laser was stabilized to a methane transition in this experiment and was used as a frequency reference instead of the Cs fountain clock. The frequency of this laser has been calibrated at the Physikalisch Technische Bundesanstalt Braunschweig/Germany (PTB) and in our own laboratory [51] to within a few parts in 1013. 

Johannsmeyer, U. and Kraemer, M. Interconnection of non-linear and linear intrinsically safe circuits, PTB-Report ThEx-10, Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin/Germany, 2000... 

So, in a research project, PTB Physikalisch-Technische Bundesanstalt, Germany, has investigated the influence of real cables on spark ignition theoretically and in practical trials using the spark test apparatus. ... 

Compared with DC, particular difficulties arise from reflections on the cable in the mismatched state by application of alternating current in a higher frequency range (Fig. 6.240). This fact results in functional and safety-related problems, which may be controlled by restriction to relatively short cables and by applying the AC safety control circuit as established by PTB Physikalisch-Technische Bundesanstalt, Germany. 

PTB Physikalisch-Technische Bundesanstalt Braunschweig and Berlin/Germany PROFIBUS Nutzerorganisation Karlsruhe/ Germany... 

Arnold, D., Jagielak, J., Kolb, W., Pietruszewski, A., Wershofen, H. and Zarucki, R., Practical experience in and improvements to aerosol sampling for trace analysis of airborne radionuclides in ground level air. PTB-Report PTB-Ra-34, Physikalishc-Technische Bundesanstalt, Braunschweig, Germany, ISSN 0341-6747, ISBN 3-89429-436-1. 

Wershofen H. and Arnold, D., Radionuclides in ground-level air in Braunschweig—a report of the PTB trace survey station for 1993 and 1994. PTB-6.33-95-3, Braunschweig, Germany, December 1995. 

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