Metrology in Gas Analysis at the Federal Office of Metrology METAS

Gas analysis as a metrological discipline has a history of about 25 years in Switzerland. Starting with the requirement of reliable reference gas mixtures for legal applications the Swiss Federal Office of Metrology (METAS) had to increasingly find also calibration solutions for the ambient air level. Thereby the metrological principles of traceability, uncertainty evaluation and verification as well as the use of unambiguous terminology for quantities and units were in the focus of the activities. Using three examples different ways of implementing these principles are explained. For the emission range, traceability is mainly achieved by gravimetrically prepared certified gas mixtures in pressurised cylinders using high purity gases and a highly reproducible comparison method. The reactivity and limited stability of the important analytes in the ambient range ask for dynamic methods to secure traceability to the international system of units (SI). The dynamic methods requiring additionally high accuracy gas flow measurement techniques and trace gas analysis will be the focus for further developments at METAS

No Rationale for a Redefinition of the Mole

In the wake of the redefinition of the kilogram, the last unit of the International System of Units (SI) that is still based on a man-made artefact, discussions were launched on the necessity of redefining other units, amongst other the unit mole. Since 1971 the mole is defined as the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12. The symbol of the unit is 'mol'. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles. The definition is based on the pre-existing choice to set the relative atomic mass of carbon 12 equal to 12 exactly. In the proposed new definition the mole is the amount of substance containing exactly 6.022 141 79 × 1023 atoms or molecules, ions, electrons, other particles, or specified groups of such particles, i.e. the Avogardo constant would have a fixed value without an uncertainty. This contribution critically examines the submitted arguments to justify the proposed redefinition of the unit mole by 2011 for their persuasive power to change a scientific and cultural good such as a unit of measurement. As shown, there are no convincing scientific arguments for a redefinition of the mole that stand a closer examination. The current definition is well understood, established in science and technology for almost 50 years and is still up to date

Effect of moisture on the adsorption of ammonia

The effect of moisture on the adsorption of ammonia was systematically studied using different surface materials and humidity levels. The experimental water amount fractions varied between 6 and 18,000 mu molmol(-1), and the ammonia amount fraction was 400nmolmol(-1). The investigated materials included plain 316L stainless steel and stainless steel cured with Dursan, SilcoNert 2000 and halocarbon wax coatings. Furthermore, Teflon (PTFE) and polyvinylidene difluoride (PVDF) polymer surfaces were studied. Dynamically diluted ammonia, test tubes prepared with the investigated materials, a commercial ammonia analyzer based on cavity ring-down spectroscopy, and a commercial dew-point transmitter were employed. The adsorption was assessed quantitatively using continuous flow conditions and real-time monitoring of the adsorption process. The ammonia adsorption was found to increase substantially in dry conditions for all the studied materials except PVDF. The increase was largest for plain stainless steel which was the most adsorbing material. The coatings applied on stainless steel decreased the adsorption significantly in dry conditions. Polymers PVDF and PTFE were the least-adsorbing materials. In water amount fractions between 1000 and 10,000 mu mol mol(-1), the ammonia adsorption was at its lowest. The adsorption increased again above 1% humidity levels.Peer reviewe

Final publishable JRP summary for ENV55 MetNH3 - Metrology for Ammonia in Ambient Air

This project developed reference standards and measurement techniques for traceable measurements of NH3 in air. These will enable validated high quality ammonia measurement data which will help monitor and compare NH3 levels and ensure compliance with environmental protection policies and legislation

MetNH3: Metrology for Ammonia in Ambient Air

Measuring ammonia in ambient air is a sensitive and priority issue due to its harmful effects on human health and ecosystems. Ammonia is increasingly being globally acknowledged as a key precursor to atmospheric particulate matter. The European Directive 2001/81/EC on “National Emission Ceilings for Certain Atmospheric Pollutants (NEC)” regulates ammonia emissions in the member states. However, due to the chemical characteristics of ambient ammonia traceable on-line measurements still have significant challenges in analytical technology, uncertainty, quality assurance and quality control (QC/QA). Currently the UK National Ammonia Monitoring Network uses an accredited off-line low temporal resolution and on-line denuder–IC methods at the UK Supersites. There is a need for traceable ammonia measurements which will be vitally important for identifying changes in environment policies, climate and agricultural practice. This in turn should lead to improvements emission inventory uncertainties and for providing independent verification of atmospheric model predictions. MetNH3 (EMRP Joint Research Project) has worked with SMEs in testing improved reference gas mixtures by static and dynamic gravimetric generation methods, develop and refine existing laser based optical spectrometric standards and establishing the transfer from high-accuracy standards to field applicable methods. The first results from the metrological characterisation of a commercially available cavity ring-down spectrometer (CRDS) are presented and the results from a new design “Controlled Atmosphere Test Facility (CATFAC)”, which is currently characterising the performance of diffusive samplers. The range and characteristics of instruments are discussed. The plans for a major ammonia field intercomparison in 2016 will be outlined

Tracing digital transformation in educational organizations

This chapter describes the quantitative approaches for assessing various aspects of digital transformation from the joint research and development project #ko.vernetzt. In an application-oriented case study approach, the operationalization of a maturity model of digital transformation for educational organizations (MMEO) and the design and implementation of a multi-perspective evaluation concept are outlined. While the MMEO provides a state perspective on the digital transformation of an educational organization and its employees, the evaluation concept aims at tracing developments of media-related professional competencies. MMEO has been implemented in a study with N = 222 participants, while N = 59 learners were subject to the evaluation polls. The results provide the necessary evidence for implementing and continuously improving a qualification program in the regarded research context. However, the methodology can also be transferred to other organizations in the education sector and beyond

Metrology for Ammonia in Ambient Air. Final publishable JRP report

This project developed reference standards and measurement techniques for traceable measurements of NH3 in air. These will enable validated high quality ammonia measurement data which will help monitor and compare NH3 levels and ensure compliance with environmental protection policies and legislation