Mirage-effect measurement of thermal diffusivity. Part II: theory

1986 ◽  
Vol 64 (9) ◽  
pp. 1168-1171 ◽  
Author(s):  
P. K. Kuo ◽  
E. D. Sendler ◽  
L. D. Favro ◽  
R. L. Thomas
Keyword(s):  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Probe Beam ◽  
Three Dimensional ◽  
Sample Surface ◽  
Bulk Sample ◽  
Effect Measurement ◽  
Dimensional Theory ◽  
Mirage Effect ◽  
Effect Technique

A three-dimensional theory of a mirage-effect technique for measuring thermal diffusivity of solids is presented. A formula that incorporates sizes and separations of the heating and probe beams; the height of the probe beam above the sample surface; the thermal properties of the sample, the gas, and the backing; and the thickness of the sample is developed. The results are compared with experiments on a bulk sample and on thin slabs of various thicknesses.

Optical Depth Profiling of Thin Films by Impulse Mirage Effect Spectroscopy. Part I: Theory

1994 ◽  
Vol 48 (9) ◽  
pp. 1054-1075 ◽  
Author(s):  
M. A. Schweitzer ◽  
J. F. Power
Keyword(s):  
Probe Beam ◽  
Fluid Layer ◽  
Three Dimensional ◽  
Depth Profiling ◽  
Depth Resolution ◽  
Beam Deflection ◽  
Theoretical Expression ◽  
Mirage Effect ◽  
Photothermal Deflection ◽  
Effect Method

Impulse mirage effect/photothermal deflection spectrometry may be used to detect depth-dependent optical absorption in materials, through the time dependence of the probe beam deflection signal occurring in response to sample irradiation with a short excitation pulse. In this work a theoretical expression was derived for the normal and transverse photothermal deflection signals which occur in a sample with homogeneous thermal properties but where optical absorptivity varies with depth from the surface. An analytical solution of moderate simplicity is obtained for several cases of experimental interest, with three-dimensional heat conduction effects included. The depth profile resolution obtained with the mirage effect method is critically dependent on the distance between the sample layer probed and the offset position of the probe beam in the fluid layer above the sample. Saturation conditions and conditions for obtaining optimal depth resolution of continuous and discrete optical profiles are examined in detail.

Thermal Expansion-Recovery Microscopy (ThERM) for microstructural characterization

2013 ◽  
Vol 1526 ◽  
Author(s):  
Esteban A. Domené ◽  
Nélida Mingolo ◽  
Oscar E. Martínez
Keyword(s):  
Thermal Expansion ◽  
Thermal Diffusivity ◽  
Probe Beam ◽  
Pump Beam ◽  
Surface Deformation ◽  
Modulation Frequency ◽  
Microstructural Characterization ◽  
Sample Surface ◽  
Beam Size ◽  
Detection Schemes

ABSTRACTIn this work we compare two different detection schemes that are sensitive to the focus shift of a probe beam due to induced surface curvature. The technique on which both detection schemes are based is called ThERM (Thermal Expansion-Recovery Microscopy) and allows the retrieval of the thermal diffusivity at microscopic levels, hence mapping such magnitude over a sample surface. The induced thermal expansion defocuses the probe beam due to the surface deformation (curvature). The dependence of the defocusing with the pump modulation frequency yields the thermal diffusivity of the sample at the impinging location. The explored depth is controlled by the pump beam size. By scanning both beams, a complete map of the thermal diffusivity can be retrieved.

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.

Mirage-effect measurement of thermal diffusivity. Part I: experiment

1986 ◽  
Vol 64 (9) ◽  
pp. 1165-1167 ◽  
Author(s):  
P. K. Kuo ◽  
M. J. Lin ◽  
C. B. Reyes ◽  
L. D. Favro ◽  
R. L. Thomas ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Thermal Wave ◽  
Compound Semiconductor ◽  
Effect Measurement ◽  
Semiconductor Materials ◽  
Wave Method ◽  
Mirage Effect ◽  
Thermal Wave Method ◽  
Thermal Diffusivities

A mirage-effect thermal-wave method for the measurement of thermal diffusivities of solids is described. Data from two different laboratories are provided for various pure elements and compound semiconductor materials. In most cases the agreement with literature values is good.

Collinear mirage effect measurement of the thermal diffusivity in Ferronematics

1998 ◽  
Vol 72 (6) ◽  
pp. 674-676 ◽  
Author(s):  
S. M. Shibli ◽  
A. L. L. Dantas ◽  
D. Walton
Keyword(s):  
Thermal Diffusivity ◽  
Effect Measurement ◽  
Mirage Effect

Membrane theory

2017 ◽  
Author(s):  
David J. Steigmann
Keyword(s):  
Three Dimensional ◽  
Thin Sheets ◽  
Two Dimensional ◽  
Leading Order ◽  
Membrane Theory ◽  
Dimensional Theory ◽  
Small Thickness

This chapter develops two-dimensional membrane theory as a leading order small-thickness approximation to the three-dimensional theory for thin sheets. Applications to axisymmetric equilibria are developed in detail, and applied to describe the phenomenon of bulge propagation in cylinders.

Thermal Characterization of Carbon-Carbon Composites

2011 ◽  
Author(s):  
Messiha Saad ◽  
Darryl Baker ◽  
Rhys Reaves
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Critical Role ◽  
Carbon Composite ◽  
Flash Method ◽  
Carbon Composites ◽  
Energy Storage Devices ◽  
Graphitized Carbon

Thermal properties of materials such as specific heat, thermal diffusivity, and thermal conductivity are very important in the engineering design process and analysis of aerospace vehicles as well as space systems. These properties are also important in power generation, transportation, and energy storage devices including fuel cells and solar cells. Thermal conductivity plays a critical role in the performance of materials in high temperature applications. Thermal conductivity is the property that determines the working temperature levels of the material, and it is an important parameter in problems involving heat transfer and thermal structures. The objective of this research is to develop thermal properties data base for carbon-carbon and graphitized carbon-carbon composite materials. The carbon-carbon composites tested were produced by the Resin Transfer Molding (RTM) process using T300 2-D carbon fabric and Primaset PT-30 cyanate ester. The graphitized carbon-carbon composite was heat treated to 2500°C. The flash method was used to measure the thermal diffusivity of the materials; this method is based on America Society for Testing and Materials, ASTM E1461 standard. In addition, the differential scanning calorimeter was used in accordance with the ASTM E1269 standard to determine the specific heat. The thermal conductivity was determined using the measured values of their thermal diffusivity, specific heat, and the density of the materials.

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