There exists a surprising theoretical prediction for a small system: its microcanonical heat capacity can become negative. An increase of energy can-under certain conditions-lead to a lower temperature. Here we present experimental evidence that a cluster containing exactly 147 sodium atoms does indeed have a negative microcanonical heat capacity near its solid to liquid transition.

In this note we present results for the heat capacity at constant pressure for the TIP4PQ/2005 model, as obtained from path-integral simulations. The model does a rather good job of describing both the heat capacity of ice I(h) and of liquid water. Classical simulations using the TIP4P/2005, TIP3P, TIP4P, TIP4P-Ew, simple point charge/extended, and TIP5P models are unable to reproduce the heat ...

We present the first experimental evidence that the heat capacity of superfluid 4He, at temperatures very close to the lambda point T(lambda), is enhanced by a constant heat flux Q. The heat capacity at constant Q, C(Q), is predicted to diverge at a temperature T(c)(Q)<T(lambda) at which superflow becomes unstable. In agreement with previous measurements, we find that dissipation enters our cel...

Previous heat capacity estimators useful in path integral simulations have variances that grow with the number of path variables included. In the present work a new specific heat estimator for Fourier path integral Monte Carlo simulations is derived using methods similar to those used in developing virial energy estimators. The resulting heat capacity estimator has a variance that is roughly in...

We present a specific heat measurement technique adapted to thin or very thin suspended membranes from low temperature (8 K) to 300 K. The presented device allows the measurement of the heat capacity of a 70 ng silicon nitride membrane (50 or 100 nm thick), corresponding to a heat capacity of 1.4 × 10(-10) J/K at 8 K and 5.1 × 10(-8) J/K at 300 K. Measurements are performed using the 3ω method ...

The thermal properties such as specific heat capacity and heat dissipation of peloids play an important role in therapeutic applications. Therefore, these properties were determined on the peloids samples taken from spas where peloid applications are used in Turkey. In addition, some pure clay minerals were investigated to determine their suitability as possible constituents of therapeutic pelo...

A model is proposed to analyze the heat transfer of deep borehole exchanger (DBHE)arrays. Based on this, a dimension reduction algorithm for numerical simulation DBHE arrays, which can improve calculation speed by several orders magnitude compared with that CFD software. An index extraction capacity (HECI) adopted evaluate arrays. The influence spacing, operation time, annual heating duration, ...

Heat pump technology has been rapidly developed recently as a clean and efficient heating method. Continuous capacity modulation of heat pumps is necessary for enhancing room thermal comfort and reducing start-stop losses. A novel capacity modulation method for the scroll compressor heat pump system based on refrigerant injection and refrigerant release is proposed. The experiments indicate the...