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Abstract  

To treat data from temperature modulated differential scanning calorimetry (TMDSC) in terms of complex or reversing heat capacity firstly one should pay attention that the response is linear and stationary because this is a prerequisite for data evaluation. The reason for non-linear and non-stationary thermal response is discussed and its influence on complex (reversing) heat capacity determination is shown. The criterion for linear and stationary response is proposed. This allows to choose correct experimental conditions for any complex heat capacity measurement. In the case when these conditions can not be fulfilled because of experimental restrictions one can estimate the influence of non-linearity and non-stationarity on measured value of complex or reversing heat capacity.

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-DSC scans were then used to calculate the total ( C p,total ), storage or reversing ( C p ′), loss ( C p ″), and non-reversing heat capacity ( C p,NR ) curves, more correctly C p measured under DSC conditions is the apparent heat capacity since

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allows a material to relax at a given temperature, which should allow further differentiation. In MDSC a sinusoidal modulation is overlaid on a linear ramp. By doing this the reversing heat capacity can be separated. The reversing heat capacity is

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Journal of Thermal Analysis and Calorimetry
Authors: C. A. Gracia-Fernández, P. Davies, S. Gómez-Barreiro, Beceiro J. López, J. Tarrío-Saavedra, and R. Artiaga

the application of a modulated temperature ramp is also sinusoidal in shape, with an amplitude A HF . The reversing heat capacity, Cp rev, can be then defined as (2) where K Cp is a calibration constant, A T is the temperature

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be taken into consideration when estimating the liquid C p. Fig. 4 The measured and calculated apparent reversing heat capacity versus temperature, after annealing at 120 °C, for dry films of: a A

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Abstract  

The quality of measurement of heat capacity by differential scanning calorimetry (DSC) is based on the symmetry of the twin calorimeters. This symmetry is of particular importance for the temperature-modulated DSC (TMDSC) since positive and negative deviations from symmetry cannot be distinguished in the most popular analysis methods. Three different DSC instruments capable of modulation have been calibrated for asymmetry using standard non-modulated measurements and a simple method is described that avoids potentially large errors when using the reversing heat capacity as the measured quantity. It consists of overcompensating the temperature-dependent asymmetry by increasing the mass of the sample pan.

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flow or isobaric apparent heat capacity curve ( C p,total ), the same as a conventional DSC curve), the in-phase curve (reversing or storage C p ) and out-of-phase curve (loss C p ) [ 11 ]. In addition, a non-reversing heat capacity (kinetic) curve

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Flour starch thermal characteristics

Modulated scanning calorimetric study

Journal of Thermal Analysis and Calorimetry
Authors: L. Haynes and M. Schuenzel

. Results Total and reversing heat capacity for a sapphire disc, no pan, was measured using either a 40, 60, or 80 s period for overall heating rate of 5 °C min −1 and 10 °C min −1 . The total range in heat capacity values measured under these

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]. Previous study based on the specific reversing heat capacity of PET/silica, electrospun nanocomposite fibers [ 15 ] demonstrated the existence of the rigid amorphous phase in the absence of PET crystallinity. Experimental results show that the rigid

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Journal of Thermal Analysis and Calorimetry
Authors: C. Gracia-Fernández, J. Tarrío-Saavedra, J. López-Beceiro, S. Gómez-Barreiro, S. Naya, and R. Artiaga

Lissajoux figures obtained in a modulated quasi-isothermal ( a ) and a modulated ramp ( b ) experiments Figure 5 displays the total heat flow, reversing heat capacity, Cp rev , and time derivative of

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