Thermogravimetric Analyzer

Two known cold masses calibrate gain and offset; a third mass is withheld. Two reference baths calibrate each thermometer; a third checks it. A known load step calibrates balance response and an independent step checks it. An empty-pan ramp estimates thermal and time drift; a separate inert specimen verifies the complete correction. All reference values and hardware dimensions are synthetic teaching definitions.

Upward buoyancy and gas drag reduce apparent mass. Matched blanks remove the pan and reproducible drift; the specimen’s own displaced volume needs a separate correction. The gold observed curve uses feed-gas density. Reaction products can alter chamber density, so the purple kinetic mass additionally depends on the fitted product-gas balance. Its activation energy assumes one first-order forward branch, known carbon dioxide inhibition and constant displaced volume. Two ramps fit the parameters; the slower third ramp never enters that fit.

A derivative peak is a scan-dependent rate maximum, not an equilibrium decomposition temperature or a chemical identifier. A single constant-temperature rate cannot separate activation energy from its prefactor. Missing final tails, unresolved loss, incompatible references and failed withheld predictions stop kinetic reporting. No complete uncertainty interval is supplied: reference, volume, mass, gas-law and thermal-model uncertainty are not fully propagated. The observed derivative includes balance lag and a twenty-second smoothing window.

Geometry is in millimetres. One pan hangs from a null-balance beam outside the furnace; an electromagnetic coil compensates its force and a capacitive sensor detects position. The mechanical null loop is idealized fast; the acquired current readback has its own finite response. A separate nitrogen purge protects the balance. The main gas crosses the pan and exits through the side port; arrows summarize a well-mixed two-cubic-centimetre chamber. The measured sample temperature is assumed representative of a lumped specimen. A synthetic initial density of one point five milligrams per cubic millimetre sets its volume, which stays fixed as mass escapes. Furnace and specimen store sensible heat; the declared reaction absorbs heat. Gas density follows an ideal-gas mixture, and flow modifies a declared effective heat conductance. Internal gradients, reverse reaction, multiple steps, turbulence, corrosion and evolved-gas spectroscopy are omitted. Hot colour and moving gas markers are schematic, not emitted light or resolved fluid trajectories.