Determination of thermal diffusivity of solid materials near the melting point

1982 ◽  
Vol 3 (1) ◽  
pp. 79-87 ◽  
Author(s):  
M. Lamvik
Keyword(s):  
Thermal Diffusivity ◽  
Melting Point ◽  
Solid Materials

scholarly journals Improvement of the photoacoustic response in thermal diffusivity measurements

2020 ◽  
Vol 3 (4) ◽  
pp. 196-205
Author(s):  
David Gasca-Figueroa ◽  
Micael Gerardo Bravo-Sánchez ◽  
Adriana Guzmán-López ◽  
José Guadalupe Zavala-Villalpando ◽  
Francisco Javier García-Rodríguez
Keyword(s):  
Mathematical Model ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Room Temperature ◽  
Heat Energy ◽  
Photoacoustic Cell ◽  
Solid Materials ◽  
Diffusivity Measurements ◽  
Materials Used

An alternative photoacoustic cell configuration for the determination of the thermal diffusivity (α), at room temperature, for solid materials is presented. The method is based on the use of two identical photoacoustic chambers, inside both of them, a metallic foil thermally thin is used to transform the light energy to heat energy.  A Reference material placed parallel to a study material allows to relate the thermal properties of the materials used as support in the photoacoustic chambers of the experimental arrangement presented here. The ratio between experimental and theoretical photoacoustic amplitudes is realized to validate a proposed mathematical model.

scholarly journals Determination of Thermal Diffusivity of Austenitic Steel Using Pulsed Infrared Thermography

2014 ◽  
Vol 59 (3) ◽  
pp. 893-897 ◽  
Author(s):  
K. Kochanowski ◽  
W. Oliferuk ◽  
Z. Płochocki ◽  
A. Adamowicz
Keyword(s):  
Thermal Diffusivity ◽  
Austenitic Steel ◽  
Infrared Thermography ◽  
Theoretical Basis ◽  
Room Temperature ◽  
Experimental Results ◽  
Solid Materials ◽  
Simple Method ◽  
Pulsed Infrared Thermography

Abstract The simple method of determining thermal diffusivity of solid materials at room temperature using the pulsed infrared thermography (IRT) is proposed. The theoretical basis of the method and experimental results are presented. The study was conducted on austenitic steel 316L. Theobtained results show that the thermal diffusivity value of the tested steel determined by means of pulsed infrared thermography is very approximate to the values given in the literature, obtained by using more complicated methods. The differences between these values are 0.5%.

EINE CHEMISCHE METHODE ZUR BESTIMMUNG VON 16-EPI-ÖSTRIOL IM URIN DES MENSCHEN

1963 ◽  
Vol 44 (1) ◽  
pp. 47-66 ◽  
Author(s):  
W. Nocke ◽  
H. Breuer
Keyword(s):  
Melting Point ◽  
Phosphoric Acid ◽  
Aqueous Alkali ◽  
Percentage Error ◽  
Organic Layer ◽  
Maximum Percentage ◽  
Chemical Determination ◽  
Routine Assay ◽  
Hydrolysis Of

ABSTRACT A method for the chemical determination of 16-epi-oestriol in the urine of nonpregnant women with a qualitative sensitivity of less than 0.5 μg/24 h is described. The separation of 16-epi-oestriol and oestriol is accomplished by converting 16-epi-oestriol into its acetonide, a reaction which is stereoselective for cis-glycols and therefore not undergone by oestriol as a trans-glycol. Following partition between chloroform and aqueous alkali, the acetonide of 16-epi-oestriol is completely separated with the organic layer whereas oestriol as a strong phenol remains in the alkaline phase. 16-epi-oestriol is chromatographed on alumina as the acetonide and determined as a Kober chromogen. This procedure can easily be incorporated into the method of Brown et al. (1957 b) thus making possible the simultaneous routine assay of oestradiol-17β, oestrone, oestriol and 16-epi-oestriol from one sample of urine. The specificity of the method was established by separation of 16-epi-oestriol from nonpregnancy urine as the acetonide, hydrolysis of the acetonide by phosphoric acid, isolation of the free compound by microsublimation and identification by micro melting point, colour reactions and chromatography. The accuracy of the method is given by a mean recovery of 64% for pure crystalline 16-epi-oestriol when added to hydrolysed urine in 5–10 μg amounts. The precision is given by s = 0.24 μg/24 h. For the duplicate determination of 16-epi-oestriol the qualitative sensitivity is 0.44 μg/24 h, the maximum percentage error being ± 100% The quantitative sensitivity (±25% error) is 1.7 μg/24 h.

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