Thermal diffusivity measurement using photoacoustic and thermal lens techniques

The open photoacoustic cell (OPC) technique was used for measuring thermal diffusivity of solid samples. It is based upon the measurement of the photoacoustic signal as a function of the modulation frequency in the region where the thermal diffusion length equals to the-sample thickness. The meas...

Full description

Saved in:

Bibliographic Details
Main Author:	Chin, Fanny Yee Ju
Format:	Thesis
Language:	English English
Published:	2000
Subjects:	Thermal diffusivity - Measurements Optoacoustic spectroscopy
Online Access:	http://psasir.upm.edu.my/id/eprint/9105/1/FSAS_2000_30%20IR.pdf
Tags:	Add Tag No Tags, Be the first to tag this record!

id	my-upm-ir.9105
record_format	uketd_dc
spelling	my-upm-ir.91052024-03-27T04:46:51Z Thermal diffusivity measurement using photoacoustic and thermal lens techniques 2000-05 Chin, Fanny Yee Ju The open photoacoustic cell (OPC) technique was used for measuring thermal diffusivity of solid samples. It is based upon the measurement of the photoacoustic signal as a function of the modulation frequency in the region where the thermal diffusion length equals to the-sample thickness. The measurements were carried out at room temperature for samples metal, alloy, semiconductor, polymer and superconductor. The measured thermal diffusivity values for metal, semiconductor and polymer samples are in good agreement with the values reported previously by other researchers. The thermal diffusivity values of the AgxAu1-x alloys decrease from 1.48 cm2/s (pure Ag) to a minimum value at around x = 0.70 before increasing towards the value of 1.28 cm2/s (pure Au). In AuxCu(l00-x)07Ag(l00-x)O.3 alloy system, the thermal diffusivity values decrease with the increasing of the weight fraction x and reaching a minimum at around x = 90 composition. Then, the thermal diffusivity values tend to increase to the value of 1.28 cm2/s for the pure Au metal. For superconductor samples in the normal state, the measured thermal diffusivity decreases with the increase of Zn content in the BbPbo.6Sr2Ca2-xZnxCu30o system, However, the thermal diffusivity values increase with the increasing of Ba dopant in the Bi2Pbo.6Sr2Ca2-xBaxCu30o system. The OPC detection was also used to monitor the evaporation time of the liquid samples. The evaporation time for 10.60 mm3 of acetone, chloroform, methanol and ethanol samples were recorded as 236.7s, 578.8s, 436.2s and 869.2s respectively. The results also show that the liquid evaporation time is inversely proportional to the laser power. The laser beam power in the range of (2-16) m W was monitored by using OPC, closed photoacoustic cell (CPC) and piezoelectric (PZT) detections. In each case, the photoacoustic (PA) signals were found to be linear up to the laser power of 16 m W. In comparison, the power meter responsivity for CPC detection always higher than OPC and followed by PZT detection. Finally, the thermal lens technique was used to determine the thermal diffusivity of liquid samples. The phenomenon of thermal lensing is due to the refractive index change with temperature in a liquid medium causes by the periodic photothermal heating. The change of the refractive index will turn the heated medium into a lens. By measuring the time dependence of the laser intensity change after passed though the thermal lens, the thermal diffusivity of the sample can be obtained. In this work, the measurements were carried out for various solvents, fuel, palm oils and chitosan at different concentration. It was found that the thermal lens technique was suitable for measuring thermal diffusivity value of liquids in the range of (9.09 x 10-4 - 12. 1 X 10-4) cm2/s. Thermal diffusivity - Measurements Optoacoustic spectroscopy 2000-05 Thesis http://psasir.upm.edu.my/id/eprint/9105/ http://psasir.upm.edu.my/id/eprint/9105/1/FSAS_2000_30%20IR.pdf text en public masters Universiti Putra Malaysia Thermal diffusivity - Measurements Optoacoustic spectroscopy Faculty of Environmental Studies Mat Yunus, Wan Mahmood English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
advisor	Mat Yunus, Wan Mahmood
topic	Thermal diffusivity - Measurements Optoacoustic spectroscopy
spellingShingle	Thermal diffusivity - Measurements Optoacoustic spectroscopy Chin, Fanny Yee Ju Thermal diffusivity measurement using photoacoustic and thermal lens techniques
description	The open photoacoustic cell (OPC) technique was used for measuring thermal diffusivity of solid samples. It is based upon the measurement of the photoacoustic signal as a function of the modulation frequency in the region where the thermal diffusion length equals to the-sample thickness. The measurements were carried out at room temperature for samples metal, alloy, semiconductor, polymer and superconductor. The measured thermal diffusivity values for metal, semiconductor and polymer samples are in good agreement with the values reported previously by other researchers. The thermal diffusivity values of the AgxAu1-x alloys decrease from 1.48 cm2/s (pure Ag) to a minimum value at around x = 0.70 before increasing towards the value of 1.28 cm2/s (pure Au). In AuxCu(l00-x)07Ag(l00-x)O.3 alloy system, the thermal diffusivity values decrease with the increasing of the weight fraction x and reaching a minimum at around x = 90 composition. Then, the thermal diffusivity values tend to increase to the value of 1.28 cm2/s for the pure Au metal. For superconductor samples in the normal state, the measured thermal diffusivity decreases with the increase of Zn content in the BbPbo.6Sr2Ca2-xZnxCu30o system, However, the thermal diffusivity values increase with the increasing of Ba dopant in the Bi2Pbo.6Sr2Ca2-xBaxCu30o system. The OPC detection was also used to monitor the evaporation time of the liquid samples. The evaporation time for 10.60 mm3 of acetone, chloroform, methanol and ethanol samples were recorded as 236.7s, 578.8s, 436.2s and 869.2s respectively. The results also show that the liquid evaporation time is inversely proportional to the laser power. The laser beam power in the range of (2-16) m W was monitored by using OPC, closed photoacoustic cell (CPC) and piezoelectric (PZT) detections. In each case, the photoacoustic (PA) signals were found to be linear up to the laser power of 16 m W. In comparison, the power meter responsivity for CPC detection always higher than OPC and followed by PZT detection. Finally, the thermal lens technique was used to determine the thermal diffusivity of liquid samples. The phenomenon of thermal lensing is due to the refractive index change with temperature in a liquid medium causes by the periodic photothermal heating. The change of the refractive index will turn the heated medium into a lens. By measuring the time dependence of the laser intensity change after passed though the thermal lens, the thermal diffusivity of the sample can be obtained. In this work, the measurements were carried out for various solvents, fuel, palm oils and chitosan at different concentration. It was found that the thermal lens technique was suitable for measuring thermal diffusivity value of liquids in the range of (9.09 x 10-4 - 12. 1 X 10-4) cm2/s.
format	Thesis
qualification_level	Master's degree
author	Chin, Fanny Yee Ju
author_facet	Chin, Fanny Yee Ju
author_sort	Chin, Fanny Yee Ju
title	Thermal diffusivity measurement using photoacoustic and thermal lens techniques
title_short	Thermal diffusivity measurement using photoacoustic and thermal lens techniques
title_full	Thermal diffusivity measurement using photoacoustic and thermal lens techniques
title_fullStr	Thermal diffusivity measurement using photoacoustic and thermal lens techniques
title_full_unstemmed	Thermal diffusivity measurement using photoacoustic and thermal lens techniques
title_sort	thermal diffusivity measurement using photoacoustic and thermal lens techniques
granting_institution	Universiti Putra Malaysia
granting_department	Faculty of Environmental Studies
publishDate	2000
url	http://psasir.upm.edu.my/id/eprint/9105/1/FSAS_2000_30%20IR.pdf
_version_	1804888545430601728

Thermal diffusivity measurement using photoacoustic and thermal lens techniques

Similar Items