Calorimeter

About: Calorimeter is a research topic. Over the lifetime, 5878 publications have been published within this topic receiving 77157 citations.

The Specific Heat of Sea Water

Abstract: There are many calculations in oceanography which involve the specific heat of sea water; this had not until now been determined to the precision desirable, and the temperature coefficient of C$\_{p}$ had not been measured. An electrically heated calorimeter has been used to determine the specific heat of sea water over approximately the ranges of temperature and salinity occurring in nature. The results are considered accurate to 0$\cdot $05%; previously accepted values are shown to be seriously in error. The temperature coefficient of C$\_{p}$ is shown to be positive for ocean water, while over the same range it is negative for pure water. An expression has been derived from which C$_{p}$ can be computed over the ranges of 0 to 40 g/kg of salt and -2 to 30 degrees C, and tabulated values are given. In testing the calorimeter the specific heat of ethanol was redetermined. Although incidental, the results are included as they are thought to be more reliable over the range of temperature covered than those previously published.

Heat capacity and thermodynamic properties of p‐terphenyl: Study of order–disorder transition by automated high‐resolution adiabatic calorimetry

Abstract: The heat capacity of a sample of zone‐refined, high‐purity p‐terphenyl has been determined from 4 to 370 K in a fully automated high‐resolution vacuum adiabatic calorimeter and from 320 to 580 K in a differential scanning calorimeter. The melting point of p‐terphenyl is 487.0 K and the enthalpy of fusion is 35.3 kJ/mol. A λ‐type solid–solid transition occurs with a peak temperature of 193.55 K. The transition is highly reproducible without observable hysteresis, even after various thermal treatments. In the transition region which spans from 140 to 240 K, the sample reaches a state of thermal equilibrium within a period of one‐half to one hour, as normally required in adiabatic calorimetry. These characteristics are desirable for the application of the equilibrium λ transitions as a calibration standard for use in dynamic calorimetry. The behavior of the λ transition at equilibrium is mapped in high temperature resolution, with small temperature increments of measurement down to 0.01 K by adiabatic calori...

Heat transfer in symmetric U-shaped microreactors for thin film calorimetry

Abstract: We describe the results of two-dimensional finite difference analysis of the thermal profile, in both transient and steady state, of a symmetric U-shape designed high-sensitive nanocalorimeter. The thin film calorimeter, with a heat capacity of 100 nJ K−1 at room temperature, consists of a 180 nm thick freestanding silicon-rich nitride membrane on which thin film heaters and sensors are deposited. Simulated temperature profiles are in good agreement with in situ experimental data obtained at the heater and sensor locations. The first-order solid-to-liquid transition of indium films, from a few A to hundreds of nm thick, was used as an experimental reference of the thermal profiles obtained from the 2D modeling. Temperature differences inside the sample region induced by the symmetric U-shape design of the Pt heaters limit the use of the nanocalorimeter to two different heating rate regimes. At low heating rates, β < 10 K s−1, especially with a thermal layer, the temperature profile is reasonably flat so that small samples can be characterized in power compensation mode. At heating rates faster than 4 × 104 K s−1 the nanocalorimeter works in adiabatic mode and measures transitions occurring in the sample directly loaded underneath the heater.