STUDY OF THERMAL TRANSPORT PARAMETERS IN PbI2 SINGLE CRYSTAL USING A PHOTOACOUSTIC TECHNIQUE

2006 ◽  
Vol 20 (20) ◽  
pp. 1253-1260 ◽  
Author(s):  
D. S. AHLAWAT ◽  
D. MOHAN ◽  
S. K. GHOSHAL ◽  
R. D. SINGH ◽  
MEENAKSHI SHARMA
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Single Crystal ◽  
Characteristic Frequency ◽  
Modulation Frequency ◽  
Thermal Effusivity ◽  
Photoacoustic Signal ◽  
Photoacoustic Technique ◽  
Front Side ◽  
Transport Parameters

The present work discusses the study of the transport properties of the PbI 2 single crystal using an indigenously developed photoacoutistic spectrometer. The amplitude photoacoustic signal, being a function of the modulation frequency of the incident optical beam, has been measured by using the front-side detection configuration. The characteristic frequency (fc) of the single crystal has been found to be 55 Hz. The values of thermal diffusivity, thermal conductivity and thermal effusivity in the case of PbI 2 have been derived experimentally. Their values have been compared with the values reported in a case which studied other materials in the literature. Thermal diffusion lengths have also been calculated at different chopping frequencies from 15 Hz to 90 Hz.

Study of thin smectic A samples by a photoacoustic technique

1986 ◽  
Vol 64 (9) ◽  
pp. 1230-1233 ◽  
Author(s):  
G. Louis ◽  
P. Peretti ◽  
J. Billard ◽  
B. Mangeot
Keyword(s):  
Phase Transitions ◽  
Liquid Crystal ◽  
Thermal Diffusivity ◽  
Modulation Frequency ◽  
Rear Surface ◽  
Photoacoustic Signal ◽  
Sample Thickness ◽  
Photoacoustic Technique ◽  
Smectic A

First we recall some experimental results about phase transitions in a thermotropic liquid crystal investigated by means of a photoacoustic technique. Then this paper examines the photoacoustic signal as a function of the sample thickness and the modulation frequency for rear-surface illumination of the smectic A sample. The results are consistent with the McDonald and Wetsel model and lead to the determination of thermal diffusivity.

Thermal Properties Measurement Photoacoustic Technique for Hardmetals

2006 ◽  
Vol 530-531 ◽  
pp. 41-47 ◽  
Author(s):  
F.A.L. Machado ◽  
Roberto da Trindade Faria Jr. ◽  
Marcello Filgueira ◽  
M.F. Rodrigues ◽  
Guerold Sergueevitch Bobrovinitchii ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Cutting Tool ◽  
Thermal Capacity ◽  
Liquid Phase Sintering ◽  
Point Of View ◽  
Photoacoustic Technique ◽  
Photoacoustic Cell ◽  
Open Photoacoustic Cell ◽  
High Pressure High Temperature

The open photoacoustic cell technique (OPC) was carried out in order to measure the thermal diffusivity of hardmetal. Hardmetal is usually processed by the conventional powder technology techniques: mix of WC + Co powders, compacting, and liquid phase sintering A new method to process hardmetal parts is hereby described. Parts of WC-15%wt Co were processed by using high pressure – high temperature sintering. It was used the pressure of 5GPa, temperature of 1350 oC, and time of 2 minutes of sintering. In addition to the thermal diffusivity, heat capacity was considered and the thermal conductivity achieved. Results matched with the values of the literatures where others photoacoustic techniques have been employed. It was achieved a thermal capacity of 3.34J/cm3K, thermal diffusivity of 0.35cm2/s, and thermal conductivity of 116.9W/mK. It reveals that the HPHT processed WC- 15%wtCo hardmetal is able to work as a cutting tool, in the thermal point of view.

scholarly journals Thermal Properties of Plaster Reinforced with Date Palm Fibers

2020 ◽  
Vol 16 (2) ◽  
pp. 259-266
Author(s):  
Mokhtar Rachedi ◽  
Abdelouahed Kriker
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Date Palm ◽  
Thermal Effusivity ◽  
Date Palm Fibers ◽  
Different Types ◽  
Local Materials ◽  
Significant Point

AbstractThis study aims both to investigate the thermal properties of plaster reinforced with date palm fibers and local natural resources valorization to batter using materials construction. For that, studying the effect of addition date palm fibers on the plaster's thermal properties is a significant point. In this work, we measured effective thermal conductivity, thermal diffusivity, specific heat, and thermal effusivity of date palm fibers reinforced plaster has been studied by CT meter. Samples configurations with four lengths (10 mm - 40 mm) and four-weight ratios (0.5 % - 2 %) of palm fibers in plaster. The results obtained demonstrate that an increase in the fraction of date palm fiber engenders to a significant decrease in the thermal conductivity, thermal diffusivity, and effusivity, even an increase for the specific heat of different types of samples. Finally, this study is a contribution to the valorization of local materials in southern Algeria, and results encourage the use of plaster and date palm fibers in the field of construction and go to eco-friendly buildings.

scholarly journals Investigation on Thermo-physical Properties of L-Valinium Picrate Single Crystal for Modern Applications

2021 ◽  
Author(s):  
M Manivannan ◽  
S. Balachandar ◽  
M. Jose ◽  
S A Martin Britto Dhas
Keyword(s):  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Physical Properties ◽  
Single Crystal ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermal Effusivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermo Physical Properties

Abstract Good quality L-valinium picrate single crystal was grown by slow evaporation technique. The lattice parameters of the crystal were measured by single crystal X-ray diffraction analysis. The High resolution X-ray diffraction study reveals good crystalline perfection of the grown crystals. The thermal diffusivity and specific heat capacity were experimentally measured using photoacoustic technique and standard DSC technique, respectively. The thermo physical properties such as thermal conductivity, thermal diffusivity, specific heat capacity, volumetric specific heat capacity, and thermal effusivity of LVP are reported for the first time at ambient temperature.

scholarly journals Thermal diffusivity of single crystal Bi0.9Sb0.1

2010 ◽  
Vol 42 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Pantelija Nikolic ◽  
S.S. Vujatovic ◽  
T. Ivetic ◽  
M.V. Nikolic ◽  
O. Cvetkovic ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Chemical Composition ◽  
Single Crystal ◽  
Electronic Transport ◽  
Modulation Frequency ◽  
Check Sample ◽  
Bridgman Technique ◽  
Amplitude Spectra ◽  
Hall Effect Measurements ◽  
Sample Homogeneity

A single crystal Bi0.9Sb0.1 ingot was synthesized using the Bridgman technique. Thermal diffusivity and electronic transport properties of single crystal cleaved plates (00l) were determined from PA photoacoustic phase and amplitude spectra obtained using the photoacoustic method with a transmission detection configuration. Both the PA phase and amplitude were measured versus the modulation frequency and numerically analyzed. EDS analyses done to determine chemical composition of the studied samples as well as to check sample homogeneity. Hall effect measurements data were used for the photoacustic measurements.

New Photothermal Deflection Method to Determine Thermal Properties of Bulk Semiconductors

2010 ◽  
Vol 297-301 ◽  
pp. 525-530
Author(s):  
Imen Gaied ◽  
Salima Lassoued ◽  
Fredéric Genty ◽  
Noureddine Yacoubi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Modulation Frequency ◽  
Phase Variation ◽  
Sample Surface ◽  
Halogen Lamp ◽  
Bulk Semiconductors ◽  
Photothermal Deflection ◽  
Modulated Light

In this paper, we present a new Photothermal Deflection Technique (PTD) to determine thermal properties of bulk doped or undoped semiconductor such as GaAs, GaSb, InAs, etc. The method proposed here consists in covering the sample with a thin graphite layer in order to increase the photothermal signal and to ovoid any reflection on the sample surface. This method deals with the analysis of the logarithm of amplitude and phase variation of the photothermal signal versus square root modulation frequency where the sample placed in air is heated by a modulated light beam coming from a halogen lamp. So the best coincidence between experimental curves and corresponding theoretical ones gives simultaneously the best values of thermal conductivity and thermal diffusivity of the sample. These obtained values are in good agreement with those found in literature. The advantage of applying this method in this way lies in its simplicity and its sensibility to both thermal conductivity and thermal diffusivity.

STUDY OF BAND GAP ENERGY AND THERMAL PROPERTIES OF PbI2 BY PHOTOACOUSTIC SPECTROSCOPY

2012 ◽  
Vol 26 (16) ◽  
pp. 1250098 ◽  
Author(s):  
DHARAMVIR SINGH AHLAWAT
Keyword(s):  
Thermal Properties ◽  
Single Crystal ◽  
Band Gap ◽  
Photoacoustic Spectroscopy ◽  
Characteristic Frequency ◽  
Band Gap Energy ◽  
Front Side ◽  
Experimental Conditions ◽  
Gap Energy ◽  
Amplitude Measurement

The present work determined the band gap energy of PbI 2 equal to 2.31 eV by amplitude measurement of the photoacoustic (PA) signal using the front side detection configuration. Furthermore, the thermal properties were obtained from the phase recording of the PA signal at the characteristic frequency 55 Hz of the single crystal (250 μm). These properties have also been compared with the earlier reported values under identical experimental conditions by amplitude recording of the PA signal on the same PA spectrometer.

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