I. Thermal Property Estimation

 

Thermal Properties in Literature

 

Pulse Decay Method

     

  • Measurement Technique of

    • - Thermal conductivity (diffusivity)

    - Blood perfusion

  • Concept

    • - Measuring temperature decay of self-heated thermistor

       probe inserted to a tissue system

  • Advantages

    • - Localized and Transient Technique

 

 

Theoretical Background

(Thermal conductivity measurement)

 

Thermal Conductivity of Various Solutions

(measured by PDM)

Han and Bischof.  ASME IMECE Proceedings 2002

 

 

Differential Scanning Calorimetry
  • Measurement Technique of

    • - Specific Heat

    - Latent Heat

  • Concept

    • - Measuring power necessary to maintain a constant rate of

       heating or cooling.  Excess power or slope vs. reference

       (differential) yields quantitative information with regard to

       thermal properties above.

  • Advantages

    • - Often the only way to measure calorimetry of phase changes

       in biomaterials (and other systems).

 

DSC - Specific Heat Measurement

Han and Bischof.  ASME IMECE Proceedings 2002

 

 

Magnitude of Latent Heat Release - PBS Solutions

Devireddy et al . IJHMT 45: 1915-1931 (2002)

 

 

Latent Heat of Various Solutions

 

Solution

Latent heat (J/g)

Phase change temperature (oC)

Total

Water/ice

Eutectic

Water/ice

Eutectic

1xNaCl-water

299.4

291.6

7.9

-0.5

-22.8

5xNaCl-water

291.5

249.7

41.8

-2.6

-22.5

10xNaCl-water

279.3

196.1

83.2

-6.0

-23.0

1xPBS

298.3

292.1

6.2

-0.5

-25.7

5xPBS

287.9

252.2

35.7

-3.0

-26.3

10xPBS

273.7

201.6

72.1

-5.9

-26.4

Han and Bischof.  ASME IMECE Proceedings 2002

 

 

Exotherms During Freezing in Biomaterials