Related Experiment Video
Updated: Jan 15, 2026

A Simple Dewar/Cryostat for Thermally Equilibrating Samples at Known Temperatures for Accurate Cryogenic Luminescence Measurements
Published on: July 19, 2016
Quenching of long-wavelength non-equilibrium temperature fluctuations in a thermophilic colloidal suspension heated
Stefano Castellini1, Alberto Vailati1
1Dipartimento di Fisica "A. Pontremoli," Università degli Studi di Milano, Milano, Italy.
Abstract:
We theoretically investigate the spatial and temporal correlation properties of non-equilibrium temperature and concentration fluctuations in a colloidal suspension of strongly thermophilic silica nanoparticles in water, characterized by a separation ratio largely smaller than -1. When the system is adiabatically heated from below, convection is suppressed, even above the Rayleigh-Bénard threshold, because nanoparticles accumulate at the bottom boundary and create a stabilizing density gradient. Under these conditions, we show that long-wavelength temperature fluctuations are quenched by the stabilizing concentration profile. Meanwhile, the macroscopic temperature gradient largely influences concentration fluctuations, reducing their overstabilization at small wave vectors. The strong thermophilic behavior of the suspension leads to a negative cross correlation between temperature and concentration fluctuations, producing a distinctive dip in the power spectrum at small wave vectors.
Related Concept Videos
Colloidal precipitates
Temperature and Thermal Equilibrium
The concept of temperature has evolved from the common concepts of hot and cold. The scientific definition of temperature explains more than just our sense of hot and cold. Temperature is operationally defined as the quantity measured with a thermometer. Furthermore, temperature is...
Colloids
Hyperthermophilic Bacteria
Physical Methods for Controlling Microbial Growth: Temperature
Diversity of Archaea IV

