100 Pure Adiabaticity: Realized with the Differential Adiabatic Calorimeter

摘要

The major shortcoming of the conventional adiabatic calorimeters, such as the accelerating rate calorimeter, is the heat capacity or thermal inertia of the sample container which acts as a heat sink, and produces misleading results under some conditions. By definition, a true adiabatic calorimeter should eliminate sample heat losses to both the environment and sample container. By carefully managing a well-controlled temperature environment, the heat loss from sample to environment can be minimized. However, the heat loss from the sample to the sample container, the so-called thermal dilution effect, has long been considered "inevitable and inherent." Conventional wisdom has held for centuries that 100% pure adiabaticity is considered a theoretical state found only at large scale, is impossible to obtain in a laboratory scale, and may only be approximated. Although the heat capacity correction, i.e. phi-factor correction has been widely used for some simple reaction systems, this approach falls short of providing real-world, timeresolved temperature and pressure curves. The correction of the complex kinetics or of the pressure data to pure adiabatic conditions is also difficult. Using an advanced adiabatic heat-compensation technique, the heat-sink effect of sample container is entirely eliminated in OmniCal differential accelerating rate calorimeters, resulting in mass- and vessel-independent, un-damped time-temperature curves which exactly match the theoretical curves. Also, because of the elimination of the container heat-sink effect, no temperature gradient is developed in the sample. Therefore, a homogeneous adiabatic environment remains -critical for testing unstirred liquids, semi-solids or powdery samples. The theoretical importance is that this new calorimeter successfully eliminates all heat losses to the environment and sample container, experimentally achieving the theoretical state of 100% true adiabaticity and the true TMRad.