Fig. 2
From: Gaseous emissions from brake wear can form secondary particulate matter
Mass spectrum of gaseous emissions from wear of brake pad material, obtained by on-line mass spectrometry. Assigned molecular formulae are annotated for the most intense peaks. The tribometer was operated at sliding speed = 4 m s−1 and contact pressure = 0.9 MPa. To eliminate background noise, the pre-experiment signal was subtracted from the signal recorded 15 min after tribometer start. For enhanced visibility, peak integration was performed for each integer mass (from n − 1/2 to n + 1/2) and the results are presented as a discrete histogram, reconstituting a mass spectrum.
