text: Figure 1 shows a typical water sorption result from a DVS measurement for a microcrystalline cellulose sample.  The kinetic data (Figure 1a) shows the change in mass and humidity as a function of time.  From the kinetic results, the rate of water uptake and water diffusion coefficients can be determined.  The equilibrium mass values at the end of each humidity step were used to calculate the sorption and desorption isotherms (Figure 1b).  The difference in water vapor uptake between the sorption and desorption isotherms is called the hysteresis.  The shape and location of the isotherm hysteresis can elucidate information about the sorption mechanism and sample porosity.  Although an isotherm experiment is the most common use of a DVS instrument, humidity- or other vapor-ramping experiments can be performed to investigate vapor-induced phase changes.  These changes include: glassy to rubbery transitions, amorphous to crystalline conversions, and sample deliquescence.