Diaphragmless shock tube for primary dynamic calibration of pressure meters

In conventional shock tubes with a diaphragm many effects related to the burst of the diaphragm can influence the shock formation and thus prevent an ideal pressure step change predicted by the shock tube measurement model being generated. This paper presents a newly developed diaphragmless shock tube, in which a diaphragm is replaced with a quick-acting pneumatic valve. The developed shock tube has a capability to generate pressure steps calculable from its measurement model with a relative expanded uncertainty of less than 0.025, which can be used as the input signal in primary calibrations of pressure meters.

Self-calibration of the 1 MN deadweight force standard machine at INRiM

The INRiM 1 MN deadweight force standard machine (DFSM) was installed in 1995. It adopts a binary sequence of ten weights whose combinations generate forces up to 1 MN. The advantage of this system lies in the self-calibration of its weights. The procedure is based on the comparison between two forces generated by a single weight and by a group of smaller weights, nominally equal. After 25 years, a verification of the DFSM was performed. Results are within the declared CMC limits, i.e. a relative expanded uncertainty of 2 × 10^-5.

Configuration and Stability of HF/SF6 and HF/N2 Standard Gases

In this paper, the analysis methods of HF components in two background series of nitrogen and sulfur hexafluoride were established and optimized. The uncertainty contribution in the weighing process was evaluated. The configuration of HF/SF6 and HF/N2 standard gases was established, that is, the packaging volume was 4L and 8L, and the content range of HF component was (50-100)×10-6 mol/mol. Then, the stability of the value of the standard gas is investigated, that is, the stability of the value with time and pressure, the fixed value and performance investigation. The relative expanded uncertainty of two series HF standard gas prediction is less than 6% (k=2).

Long-term stability of measurements of the elemental composition of steel using a vacuum atomic emission spectrometer «Grand-Expert»

A study of the repeatability and long-term stability of elemental content measurements in a UG20 standard sample using a vacuum atomic emission spectrometer «Grand-Expert» was carried out on time scales of 10 min and 1 h. The values of standard and expanded uncertainty of the results of carbon, chromium, manganese, nickel and silicon determination which characterize the repeatability and long-term stability of measurements were calculated. It has been shown that a vacuum atomic emission spectrometer «Grand-Expert» provides determination of the content of alloying elements in steel with a relative expanded uncertainty of 1 – 2% whereas measurements of carbon content are characterized by higher relative expanded uncertainty of about 3%.

International Standard for viscosity at temperatures up to 473 K and pressures below 200 MPa (IUPAC Technical Report)

This paper presents the results of an investigation into possible liquid viscosity standards to meet an industrial requirement for a liquid with a nominal viscosity of 20 mPa s at a temperature of 473 K and pressure of 200 MPa with a relative expanded uncertainty of less than 5%. There are no commercially available certified viscosity reference liquids that meet this requirement. Four candidate fluids were examined: squalane, Krytox GPL102, tris(2-ethylhexyl) trimellitate (TOTM), and dipentaerythritol hexa(3,5,5-trimethylhexanoate) (DiPEiC9). Although none of these fluids satisfies all of the criteria, two fluids were identified as being suitable as International Standards for viscosity at temperatures up to 473 K and pressures below 200 MPa. These fluids are squalane and tris(2-ethylhexyl) trimellitate (TOTM), which atT=473.15 K andp=200 MPa present viscosity values of 5 mPa s and 10 mPa s, respectively.

Development of Candidate Reference Materials of Endosulfan Sulfate and Bifenthrin in Black Tea

The candidate reference materials of endosulfan sulfate and bifenthrin in black tea have been developed according to the requirements of ISO Guide 34 and 35. Preparation of candidate material includes grinding and sieving of the black tea leaves, spiking the black tea powder by both analytes, homogenization, and bottling. Homogeneity and short-term stability test were performed using a GC-µECD instrument. Meanwhile, the characterization was carried out by a collaborative study using both of GC-µECD and GC-MS instruments. The uncertainty budget was evaluated from sample inhomogeneity, short-term instability and variability in the characterization procedure. In a dry mass fraction, endosulfan sulfate was assigned to be 491 µg kg-1 with a relative expanded uncertainty of ± 33.2%, and bifenthrin was assigned to be 937 µg kg-1 with a relative expanded uncertainty of ± 18.5%. The candidate reference materials are aimed to support the need of matrix CRM especially for the measurement of pesticide residue for quality assurance work done by laboratories in Indonesia.