For each response 10 pulses were averaged to improve the signal to noise ratio. The water response was too broad to be accurately integrated. The following m/e were used : propane 29, propene 41, carbon monoxide 28, carbon dioxide 44, water 18 and argon 40. A correction of the response signals at a specific m/e ratio was performed in the case of overlap of different substances. In all cases argon was mixed in the pulse valve as an internal standard. In order to record the fragmentation patterns and to calibrate the mass spectrometer, all reactants and products mixtures were pulsed over a quartz bed. Pulse experiments were carried out at 500, 550, 600 and 650☌. Additionally propene, CO and CO 2 were pulsed over the catalyst. The same oxygen-to-propane ratio during single pulse experiments was used as during the pretreatment. A smooth transition to the vacuum experiments was assured by first instantly switching by means of a four-way valve the reactive flow to pure nitrogen for 1 h, before exposing the reactor to the vacuum chamber. Two different propane-to-oxygen ratios were used, C 3H 8/O 2 and 0.5. The catalyst was pretreated at 550☌ by a flow of propane, oxygen and helium for 1 h at atmospheric pressure. To avoid temperature gradients over the catalyst bed, 75 mg of the catalyst (d p = 200–300 μm) was placed in the microreactor between two layers of quartz (d p = 200-300 μm), with a thermocouple inside the catalyst bed. The shape of the response reflects the diffusion, adsorption, desorption and reaction, as described in. The response of these pulses as a function of time is detected by a quadrupole mass spectrometer (QMS) located directly underneath the reactor exit. Narrow gas pulses of reactants are introduced in a microreactor (25.4 mm in length and 4 mm in diameter) which is evacuated continuously. Transient experiments under vacuum conditions were carried out in the TAP-2 (Temporal Analysis of Products) reactor.

Mirodatos, in Studies in Surface Science and Catalysis, 1999 TAP experiments. A p-chart is a form of the Individuals chart (also referred to as 'XmR' or 'ImR'), and these practitioners recommend the individuals chart as a more robust alternative for count-based data.Y.

Due to this sensitivity to the underlying assumptions, p-charts are often implemented incorrectly, with control limits that are either too wide or too narrow, leading to incorrect decisions regarding process stability. Some practitioners have pointed out that the p-chart is sensitive to the underlying assumptions, using control limits derived from the binomial distribution rather than from the observed sample variance. P ¯ = ∑ i = 1 m ∑ j = 1 n, where n i is the size of the sample that produced the ith observation on the p-chart

Calibrated size estimation chart