A method to measure thermal diffusivity around a single heated gold nanoparticle is presented. It is based on photothermal single particle microscopy and employs the phase delay of temperature modulation due to finite thermal diffusivity. The phase delay is detected optically averaging over the focal volume of a diffraction limited beam of light. Thermal diffusivity is extracted by comparison t...

A new transient Raman thermal probing technique, frequency-resolved Raman (FR-Raman), is developed for probing the transient thermal response of materials and measuring their thermal diffusivity. The FR-Raman uses an amplitude-modulated square-wave laser for simultaneous material heating and Raman excitation. The evolution profile of Raman properties: intensity, Raman wavenumber, and emission, ...

In the present work, the rear photoacoustic signal technique is used to determine thermal properties of human nails. The aging process of the human nail is analyzed through its thermal diffusivity and specific heat and using these results, thermal conductivity and thermal effusivity is determined. The study in vitro of this natural polymer showed a minimum for thermal properties to age about 20...

We report the results of a thermal wave study on SiC/B4C composites of different B4C compositions. Thermal wave, generated subsequent to sample absorption of pulse laser, was observed by means of a wide-band infrared detector. The information content of the thermal wave is then analysed by using a least-squares method. Temperature decay time, as measured from thermal wave decay curve, varies wi...

Effects of matrix cracks and the attendant interface debonding and sliding on both the longitudinal and the transverse thermal diffusivities of a unidirectional Nicalon/MAS composite are investigated. The diffusivity measurements are made in situ during tensile testing using a phase-sensitive photothermal technique. The contribution to the longitudinal thermal resistance from each of the cracks...

We report on a thermal diffusivity study of suspended graphene foam (GF) using the transient electro-thermal technique. Our Raman study confirms the GF is composed of two-layer graphene. By measuring GF of different lengths, we are able to exclude the radiation effect. Using Schuetz's model, the intrinsic thermal diffusivity of the free-standing two-layer graphene is determined with a high accu...

Cross-magnetic-field heat transport in a quiescent pure ion plasma is found to be diffusive and to be dominated by long-range ‘‘guiding center’’ collisions. In these long-range collisions, which occur in plasmas with Debye length lD greater than cyclotron radius rc , particles with impact parameters rc,r<lD exchange parallel kinetic energy only. The resulting thermal diffusivity xL is independe...

We report measurements of thermal diffusivity of several room-temperature ionic liquids (RTILs) using the transient grating method. Measurements are carried out using ionic liquids with small concentrations of an inert dye that is excited by the 532 nm output of a Nd:YAG laser in a grating with a fringe spacings of (92 and 104) μm. The experiments give thermal diffusivities from which thermal c...

The thermo physical parameters thermal effusivity (e) and thermal diffusivity (α) have been measured using Fourier transform infrared (FTIR) Photoacoustic spectroscopy (PAS) for two different purities of C60 fullerenes (99.5 % , 98.5%) samples in the powder form. The experimental results shows that the values of thermal diffusivity is less then that obtained for crystalline C60 fullerenes. The ...

In recent times, nanofluids have been studied by their thermal properties due to their variety of applications that range from photothermal therapy and radiofrequency hyperthermia (which have proven their potential use as coadjutants in these medical treatments for cancer diseases) to next-generation thermo-fluids. In this work, photoacoustic spectroscopy for a specific study of thermal diffusi...