| 1. |
- Heinonen, M., et al.
(författare)
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New Primary Standards for Establishing SI Traceability for Moisture Measurements in Solid Materials
- 2018
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Ingår i: International journal of thermophysics. - : Springer. - 0195-928X .- 1572-9567. ; 39
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Tidskriftsartikel (refereegranskat)abstract
- A European research project METefnet addresses a fundamental obstacle to improving energy-intensive drying process control: due to ambiguous reference analysis methods and insufficient methods for estimating uncertainty in moisture measurements, the achievable accuracy in the past was limited and measurement uncertainties were largely unknown. This paper reports the developments in METefnet that provide a sound basis for the SI traceability: four new primary standards for realizing the water mass fraction were set up, analyzed and compared to each other. The operation of these standards is based on combining sample weighing with different water vapor detection techniques: cold trap, chilled mirror, electrolytic and coulometric Karl Fischer titration. The results show that an equivalence of 0.2 % has been achieved between the water mass fraction realizations and that the developed methods are applicable to a wide range of materials.
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| 2. |
- Medvedevskikh, Maria, et al.
(författare)
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Report of the CCQM-K130 : Nitrogen mass fraction measurements in glycine
- 2017
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Ingår i: Metrologia. - 0026-1394 .- 1681-7575. ; 54:1A
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Tidskriftsartikel (refereegranskat)abstract
- Mass fraction of nitrogen is very important pointer because the results of these measurements are often used for determination of protein mass fraction that is an important indicator of the quality of the vast majority of food products and raw materials, in particular dry milk powder. Proteins-enzymes catalyze chemical reactions, protein along with fats and carbohydrates is one of the indicators characterizing the energy value of food, so its definition is mandatory for all food products. The aim of this key comparison CCQM-K130 and pilot study P166 is to support National Measurement Institutes (NMIs) and Designated Institutes (DIs) to demonstrate the validity of the procedures the employed for determination of nitrogen mass fraction in glycine. The study material for this key comparison and pilot study has been selected to be representative as one of the aminoacid-the simplest part of the protein. Glycine is an amino acid, single acid that does not have any isomers (melting point-290 °C; specific heat of evaporation-528,6 J/kg; specific melting heat-981,1 J/kg; pKa-2,34, molar mass-75,07 g/mol, density-1,607 g/cm3). Ural Scientific Research Institute for Metrology (UNIIM) acted as the coordinating laboratory of this comparison and pilot study. Eight NMIs participated in this key comparison and two NMIs participated in Pilot study. The results of Pilot study are excluded from the Report B.
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