Precision mass measurements

Abstract

Mass as a physical quantity and its measurement are described. After some historical remarks, a short summary of the concept of mass in classical and modern physics is given. Principles and methods of mass measurements, for example as energy measurement or as measurement of weight forces and forces caused by acceleration, are discussed. Precision mass measurement by comparing mass standards using balances is described in detail. Measurement of atomic masses related to 12 C is briefly reviewed as well as experiments and recent discussions for a future new definition of the kilogram, the SI unit of mass.

Preparation of primary standard mixtures for atmospheric oxygen measurements with less than 1 µmol mol−1 uncertainty for oxygen molar fractions

“…The adsorption effect can greatly influence mass readings of a sample cylinder by adsorption and desorption of water vapour from surrounding ambient air on the external surface of a sample cylinder (Alink et al, 2000;Mizushima, 2004Mizushima, , 2007Milton et al, 2011). The thermal effect is related to temperature gradients between a sample cylinder and the surrounding ambient air (Gläser, 1990(Gläser, , 1999Mana et al, 2002;Gläser and Borys, 2009;Schreiber et al, 2015), which is able to change the weight force of the sample cylinder through frictional forces exerted on the vertical surface of a sample cylinder and pressure forces on the horizontal surface. Both the frictional and pressure forces are caused by the upward or downward flow of air that is heated or cooled, respectively, by the sample cylinder.…”

“…For example, long-term observation allows the estimation of land biotic and oceanic CO 2 uptake (Manning and Keeling, 2006;Tohjima et al, 2008;Ishidoya et al, 2012a, b). Various measurement techniques have been developed for this purpose, including the utilization of interferometry (Keeling et al, 1998b), mass spectrometry (Bender et al, 1994;Ishidoya et al, 2003;Ishidoya and Murayama, 2014), a paramagnetic technique (Manning et al, 1999;Aoki et al, 2018;Ishidoya et al, 2017), a vacuum-ultraviolet absorption technique (Stephens et al, 2003), gas chromatography (Tohjima, 2000), and a method utilizing fuel cells (Stephens et al, 2007;Goto et al, 2013). In all these cases, calibration using standard mixtures is required to precisely determine the relationship between the analysis output and O 2 molar fractions obtained.…”

System modeling and identification of a balance type checkweigher compensated by voice coil actuator

“…Voice coil actuators (VCAs) are used due to its fast response and linear motion. 1 VCAs are used due to its fast response and linear motion. 2,3 Through measurement of current flow in the VCA, both compensation force and the weight force are determined.…”

Research on the Influence of Air Pressure to High Accuracy Mass Measurement

“…According to OIML R111 (Organisation Internationale de Metrologie Legale, Recommendation 111, Weights), altitude and corresponding changes in air density can affect the measurement process when using the conventional mass of weights, in which air pressure is a major parameter to the air density. [1] For high precise mass measurement, accurate instruments should be used to determine the temperature, pressure, relative humidity and CO2 content in air. [2][3][4]The air buoyancy correction shall be used, which requires the density of the weight to be known.…”